Merge pull request #15587 from esphome/bump-2026.4.0b1

2026.4.0b1

.ai/instructions.md

@@ -124,6 +124,28 @@ This document provides essential context for AI models interacting with this pro
     *   **Indentation:** Use spaces (two per indentation level), not tabs
     *   **Type aliases:** Prefer `using type_t = int;` over `typedef int type_t;`
     *   **Line length:** Wrap lines at no more than 120 characters
+    *   **Constructor parameters vs setters:** Component properties that are both **required** and **invariant**
+        (never change after construction) should be constructor parameters rather than set via setter methods.
+        This makes the dependency explicit and prevents use of the object in an incompletely-initialized state.
+        In code generation, when calling `cg.new_Pvariable()` or the relevant helper function to create the component, pass these as arguments.
+        ```cpp
+        // Good - required invariant dependency as constructor parameter
+        class SourceTextSensor : public text_sensor::TextSensor, public Component {
+         public:
+          explicit SourceTextSensor(text::Text *source) : source_(source) {}
+         protected:
+          text::Text *source_;
+        };
+        ```
+        ```cpp
+        // Bad - required invariant dependency as setter
+        class SourceTextSensor : public text_sensor::TextSensor, public Component {
+         public:
+          void set_source(text::Text *source) { this->source_ = source; }
+         protected:
+          text::Text *source_{nullptr};
+        };
+        ```
 
 *   **Component Structure:**
     *   **Standard Files:**
@@ -217,6 +239,123 @@ This document provides essential context for AI models interacting with this pro
               var = await switch.new_switch(config)
           ```
 
+*   **Automations (Triggers, Actions, Conditions):**
+
+    Automations have three building blocks: **Triggers** (fire when something happens), **Actions** (do something), and **Conditions** (check if something is true).
+
+    *   **Triggers -- Callback method (preferred):**
+
+        Use `build_callback_automation()` for simple triggers. This eliminates the need for a C++ Trigger class by using a lightweight pointer-sized forwarder struct registered directly as a callback. No `CONF_TRIGGER_ID` in the schema.
+
+        **Python:**
+        ```python
+        from esphome import automation
+
+        CONFIG_SCHEMA = cv.Schema({
+            cv.GenerateID(): cv.declare_id(MyComponent),
+            cv.Optional(CONF_ON_STATE): automation.validate_automation({}),
+        }).extend(cv.COMPONENT_SCHEMA)
+
+        async def to_code(config):
+            var = cg.new_Pvariable(config[CONF_ID])
+            await cg.register_component(var, config)
+            for conf in config.get(CONF_ON_STATE, []):
+                await automation.build_callback_automation(
+                    var, "add_on_state_callback", [(bool, "x")], conf
+                )
+        ```
+
+        `build_callback_automation` arguments: `parent`, `callback_method` (C++ method name), `args` (template args as `[(type, name)]` tuples), `config`, and optional `forwarder` (defaults to `TriggerForwarder<Ts...>`).
+
+        For boolean filtering (e.g. `on_press`/`on_release`), use built-in forwarders with `args=[]`:
+        ```python
+        for conf_key, forwarder in (
+            (CONF_ON_PRESS, automation.TriggerOnTrueForwarder),
+            (CONF_ON_RELEASE, automation.TriggerOnFalseForwarder),
+        ):
+            for conf in config.get(conf_key, []):
+                await automation.build_callback_automation(
+                    var, "add_on_state_callback", [], conf, forwarder=forwarder
+                )
+        ```
+
+        **C++ -- no trigger class needed.** The callback registration method must be templatized to accept both `std::function` and lightweight forwarder structs (which avoid heap allocation):
+        ```cpp
+        class MyComponent : public Component {
+         public:
+          // Must be a template -- accepts both std::function and pointer-sized forwarder structs
+          template<typename F> void add_on_state_callback(F &&callback) {
+            this->state_callback_.add(std::forward<F>(callback));
+          }
+         protected:
+          // Use CallbackManager when callbacks are always registered (e.g. core components)
+          CallbackManager<void(bool)> state_callback_;
+          // Use LazyCallbackManager when callbacks are often not registered -- saves 8 bytes
+          // (nullptr vs empty std::vector) per instance when no callbacks are added
+          // LazyCallbackManager<void(bool)> state_callback_;
+        };
+        ```
+
+    *   **Triggers -- Trigger class method:**
+
+        Use `build_automation()` with a `Trigger<Ts...>` subclass only when the forwarder needs **mutable state beyond a single `Automation*` pointer** (e.g. edge detection tracking previous state, timing logic).
+
+        **Python:**
+        ```python
+        TurnOnTrigger = my_ns.class_("TurnOnTrigger", automation.Trigger.template())
+
+        CONFIG_SCHEMA = cv.Schema({
+            cv.Optional(CONF_ON_TURN_ON): automation.validate_automation(
+                {cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(TurnOnTrigger)}
+            ),
+        })
+
+        async def to_code(config):
+            for conf in config.get(CONF_ON_TURN_ON, []):
+                trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
+                await automation.build_automation(trigger, [], conf)
+        ```
+
+        **C++:**
+        ```cpp
+        class TurnOnTrigger : public Trigger<> {
+         public:
+          explicit TurnOnTrigger(MyComponent *parent) : last_on_{false} {
+            parent->add_on_state_callback([this](bool state) {
+              if (state && !this->last_on_)
+                this->trigger();
+              this->last_on_ = state;
+            });
+          }
+         protected:
+          bool last_on_;
+        };
+        ```
+
+    *   **Actions:**
+        ```cpp
+        template<typename... Ts> class MyAction : public Action<Ts...> {
+         public:
+          explicit MyAction(MyComponent *parent) : parent_(parent) {}
+          void play(const Ts &...) override { this->parent_->do_something(); }
+         protected:
+          MyComponent *parent_;
+        };
+        ```
+        Register with `@automation.register_action("my_component.do_something", MyAction, schema, synchronous=True)`. Use `synchronous=True` for actions that run to completion inside `play()` without deferring. Use `synchronous=False` if the action may suspend/defer execution (e.g. `delay`, `wait_until`, `script.wait`) or store trigger arguments for later use.
+
+    *   **Conditions:**
+        ```cpp
+        template<typename... Ts> class MyCondition : public Condition<Ts...> {
+         public:
+          explicit MyCondition(MyComponent *parent) : parent_(parent) {}
+          bool check(const Ts &...) override { return this->parent_->is_active(); }
+         protected:
+          MyComponent *parent_;
+        };
+        ```
+        Register with `@automation.register_condition("my_component.is_active", MyCondition, schema)`.
+
 *   **Configuration Validation:**
     *   **Common Validators:** `cv.int_`, `cv.float_`, `cv.string`, `cv.boolean`, `cv.int_range(min=0, max=100)`, `cv.positive_int`, `cv.percentage`.
     *   **Complex Validation:** `cv.All(cv.string, cv.Length(min=1, max=50))`, `cv.Any(cv.int_, cv.string)`.
@@ -252,10 +391,39 @@ This document provides essential context for AI models interacting with this pro
     *   **Component Tests:** YAML-based compilation tests are located in `tests/`. The structure is as follows:
         ```
         tests/
-        ├── test_build_components/ # Base test configurations
-        └── components/[component]/ # Component-specific tests
+        ├── test_build_components/
+        │   └── common/          # Shared bus packages (uart, i2c, spi, etc.)
+        │       ├── uart/        # UART at default baud rate
+        │       ├── uart_115200/ # UART at 115200 baud
+        │       ├── i2c/         # I2C bus
+        │       └── spi/         # SPI bus
+        └── components/[component]/
+            ├── common.yaml      # Component-only config (no bus definitions)
+            ├── test.esp32-idf.yaml
+            ├── test.esp8266-ard.yaml
+            └── test.rp2040-ard.yaml
         ```
         Run them using `script/test_build_components`. Use `-c <component>` to test specific components and `-t <target>` for specific platforms.
+
+    *   **Test Grouping with Packages:** Components that use shared bus packages can be grouped together in CI to reduce build count. **Never define buses (uart, i2c, spi, modbus) directly in test YAML files** — always use packages from `test_build_components/common/`:
+        ```yaml
+        # test.esp32-idf.yaml — use packages for buses
+        packages:
+          uart: !include ../../test_build_components/common/uart_115200/esp32-idf.yaml
+
+        <<: !include common.yaml
+        ```
+        ```yaml
+        # common.yaml — component config only, NO bus definitions
+        my_component:
+          id: my_instance
+
+        sensor:
+          - platform: my_component
+            name: My Sensor
+        ```
+        Components that define buses directly are flagged as "NEEDS MIGRATION" and cannot be grouped, increasing CI build time.
+
     *   **Testing All Components Together:** To verify that all components can be tested together without ID conflicts or configuration issues, use:
         ```bash
         ./script/test_component_grouping.py -e config --all
@@ -395,6 +563,30 @@ This document provides essential context for AI models interacting with this pro
 
         Note: Avoiding heap allocation after `setup()` is always required regardless of component type. The prioritization above is about the effort spent on container optimization (e.g., migrating from `std::vector` to `StaticVector`).
 
+        **Callback Managers:**
+
+        ESPHome provides two callback manager types in `esphome/core/helpers.h` for the observer pattern. Both support `std::function`, lambdas, and lightweight forwarder structs via their templatized `add()` method.
+
+        | Type | Idle overhead (32-bit) | When to use |
+        |------|----------------------|-------------|
+        | `CallbackManager<void(Ts...)>` | 12 bytes (empty `std::vector`) | Callbacks are always or almost always registered |
+        | `LazyCallbackManager<void(Ts...)>` | 4 bytes (`nullptr`) | Callbacks are often not registered (common case) |
+
+        `LazyCallbackManager` is a drop-in replacement for `CallbackManager` that defers allocation until the first callback is added. Prefer it for entity-level callbacks where most instances have no subscribers.
+
+        **Important:** Registration methods that add to a callback manager **must always be templatized** to accept both `std::function` and pointer-sized forwarder structs (used by `build_callback_automation`). Never use `std::function` in the method signature:
+        ```cpp
+        // Bad -- forces heap allocation for forwarder structs
+        void add_on_state_callback(std::function<void(bool)> &&callback) {
+          this->state_callback_.add(std::move(callback));
+        }
+
+        // Good -- accepts any callable without forcing std::function wrapping
+        template<typename F> void add_on_state_callback(F &&callback) {
+          this->state_callback_.add(std::forward<F>(callback));
+        }
+        ```
+
     *   **State Management:** Use `CORE.data` for component state that needs to persist during configuration generation. Avoid module-level mutable globals.
 
         **Bad Pattern (Module-Level Globals):**

.clang-tidy.hash

@@ -1 +1 @@
-8e48e836c6fc196d3da000d46eb09db243b87fe33518a74e49c8e009d756074a
+f31f13994768b5b07e29624406c9b053bf4bb26e1623ac2bc1e9d4a9477502d6

.github/actions/restore-python/action.yml

@@ -22,7 +22,7 @@ runs:
         python-version: ${{ inputs.python-version }}
     - name: Restore Python virtual environment
       id: cache-venv
-      uses: actions/cache/restore@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+      uses: actions/cache/restore@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
       with:
         path: venv
         # yamllint disable-line rule:line-length

.github/scripts/auto-label-pr/detectors.js

@@ -235,19 +235,20 @@ async function detectDeprecatedComponents(github, context, changedFiles) {
     }
   }
 
-  // Get PR head to fetch files from the PR branch
-  const prNumber = context.payload.pull_request.number;
+  // Get base branch ref to check if deprecation already exists for the component
+  // This prevents flagging a PR that simply adds deprecation
+  const baseRef = context.payload.pull_request.base.ref;
 
   // Check each component's __init__.py for DEPRECATED_COMPONENT constant
   for (const component of components) {
     const initFile = `esphome/components/${component}/__init__.py`;
     try {
-      // Fetch file content from PR head using GitHub API
+      // Fetch file content from base branch using GitHub API
       const { data: fileData } = await github.rest.repos.getContent({
         owner,
         repo,
         path: initFile,
-        ref: `refs/pull/${prNumber}/head`
+        ref: baseRef
       });
 
       // Decode base64 content

.github/workflows/auto-label-pr.yml

@@ -27,7 +27,7 @@ jobs:
 
       - name: Generate a token
         id: generate-token
-        uses: actions/create-github-app-token@29824e69f54612133e76f7eaac726eef6c875baf # v2
+        uses: actions/create-github-app-token@f8d387b68d61c58ab83c6c016672934102569859 # v2
         with:
           app-id: ${{ secrets.ESPHOME_GITHUB_APP_ID }}
           private-key: ${{ secrets.ESPHOME_GITHUB_APP_PRIVATE_KEY }}

.github/workflows/ci-clang-tidy-hash.yml

@@ -40,7 +40,7 @@ jobs:
           echo "You have modified clang-tidy configuration but have not updated the hash." | tee -a $GITHUB_STEP_SUMMARY
           echo "Please run 'script/clang_tidy_hash.py --update' and commit the changes." | tee -a $GITHUB_STEP_SUMMARY
 
-      - if: failure()
+      - if: failure() && github.event.pull_request.head.repo.full_name == github.repository
         name: Request changes
         uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0
         with:
@@ -53,7 +53,7 @@ jobs:
               body: 'You have modified clang-tidy configuration but have not updated the hash.\nPlease run `script/clang_tidy_hash.py --update` and commit the changes.'
             })
 
-      - if: success()
+      - if: success() && github.event.pull_request.head.repo.full_name == github.repository
         name: Dismiss review
         uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0
         with:

.github/workflows/ci.yml

@@ -47,7 +47,7 @@ jobs:
           python-version: ${{ env.DEFAULT_PYTHON }}
       - name: Restore Python virtual environment
         id: cache-venv
-        uses: actions/cache@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
         with:
           path: venv
           # yamllint disable-line rule:line-length
@@ -106,6 +106,7 @@ jobs:
           script/build_codeowners.py --check
           script/build_language_schema.py --check
           script/generate-esp32-boards.py --check
+          script/generate-rp2040-boards.py --check
 
   pytest:
     name: Run pytest
@@ -153,12 +154,12 @@ jobs:
           . venv/bin/activate
           pytest -vv --cov-report=xml --tb=native -n auto tests --ignore=tests/integration/
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@671740ac38dd9b0130fbe1cec585b89eea48d3de # v5.5.2
+        uses: codecov/codecov-action@57e3a136b779b570ffcdbf80b3bdc90e7fab3de2 # v6.0.0
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
       - name: Save Python virtual environment cache
         if: github.ref == 'refs/heads/dev'
-        uses: actions/cache/save@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        uses: actions/cache/save@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
         with:
           path: venv
           key: ${{ runner.os }}-${{ steps.restore-python.outputs.python-version }}-venv-${{ needs.common.outputs.cache-key }}
@@ -170,6 +171,8 @@ jobs:
       - common
     outputs:
       integration-tests: ${{ steps.determine.outputs.integration-tests }}
+      integration-tests-run-all: ${{ steps.determine.outputs.integration-tests-run-all }}
+      integration-test-files: ${{ steps.determine.outputs.integration-test-files }}
       clang-tidy: ${{ steps.determine.outputs.clang-tidy }}
       clang-tidy-mode: ${{ steps.determine.outputs.clang-tidy-mode }}
       python-linters: ${{ steps.determine.outputs.python-linters }}
@@ -182,6 +185,7 @@ jobs:
       cpp-unit-tests-run-all: ${{ steps.determine.outputs.cpp-unit-tests-run-all }}
       cpp-unit-tests-components: ${{ steps.determine.outputs.cpp-unit-tests-components }}
       component-test-batches: ${{ steps.determine.outputs.component-test-batches }}
+      benchmarks: ${{ steps.determine.outputs.benchmarks }}
     steps:
       - name: Check out code from GitHub
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
@@ -194,7 +198,7 @@ jobs:
           python-version: ${{ env.DEFAULT_PYTHON }}
           cache-key: ${{ needs.common.outputs.cache-key }}
       - name: Restore components graph cache
-        uses: actions/cache/restore@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        uses: actions/cache/restore@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
         with:
           path: .temp/components_graph.json
           key: components-graph-${{ hashFiles('esphome/components/**/*.py') }}
@@ -210,6 +214,8 @@ jobs:
 
           # Extract individual fields
           echo "integration-tests=$(echo "$output" | jq -r '.integration_tests')" >> $GITHUB_OUTPUT
+          echo "integration-tests-run-all=$(echo "$output" | jq -r '.integration_tests_run_all')" >> $GITHUB_OUTPUT
+          echo "integration-test-files=$(echo "$output" | jq -c '.integration_test_files')" >> $GITHUB_OUTPUT
           echo "clang-tidy=$(echo "$output" | jq -r '.clang_tidy')" >> $GITHUB_OUTPUT
           echo "clang-tidy-mode=$(echo "$output" | jq -r '.clang_tidy_mode')" >> $GITHUB_OUTPUT
           echo "python-linters=$(echo "$output" | jq -r '.python_linters')" >> $GITHUB_OUTPUT
@@ -222,9 +228,10 @@ jobs:
           echo "cpp-unit-tests-run-all=$(echo "$output" | jq -r '.cpp_unit_tests_run_all')" >> $GITHUB_OUTPUT
           echo "cpp-unit-tests-components=$(echo "$output" | jq -c '.cpp_unit_tests_components')" >> $GITHUB_OUTPUT
           echo "component-test-batches=$(echo "$output" | jq -c '.component_test_batches')" >> $GITHUB_OUTPUT
+          echo "benchmarks=$(echo "$output" | jq -r '.benchmarks')" >> $GITHUB_OUTPUT
       - name: Save components graph cache
         if: github.ref == 'refs/heads/dev'
-        uses: actions/cache/save@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        uses: actions/cache/save@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
         with:
           path: .temp/components_graph.json
           key: components-graph-${{ hashFiles('esphome/components/**/*.py') }}
@@ -246,7 +253,7 @@ jobs:
           python-version: "3.13"
       - name: Restore Python virtual environment
         id: cache-venv
-        uses: actions/cache@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
         with:
           path: venv
           key: ${{ runner.os }}-${{ steps.python.outputs.python-version }}-venv-${{ needs.common.outputs.cache-key }}
@@ -261,9 +268,20 @@ jobs:
       - name: Register matcher
         run: echo "::add-matcher::.github/workflows/matchers/pytest.json"
       - name: Run integration tests
+        env:
+          INTEGRATION_TEST_FILES: ${{ needs.determine-jobs.outputs.integration-test-files }}
+          INTEGRATION_TESTS_RUN_ALL: ${{ needs.determine-jobs.outputs.integration-tests-run-all }}
         run: |
           . venv/bin/activate
-          pytest -vv --no-cov --tb=native -n auto tests/integration/
+          if [[ "$INTEGRATION_TESTS_RUN_ALL" == "true" ]]; then
+            echo "Running all integration tests"
+            pytest -vv --no-cov --tb=native -n auto tests/integration/
+          else
+            # Parse JSON array into bash array to avoid shell expansion issues
+            mapfile -t test_files < <(echo "$INTEGRATION_TEST_FILES" | jq -r '.[]')
+            echo "Running ${#test_files[@]} specific integration tests"
+            pytest -vv --no-cov --tb=native -n auto "${test_files[@]}"
+          fi
 
   cpp-unit-tests:
     name: Run C++ unit tests
@@ -292,6 +310,40 @@ jobs:
             script/cpp_unit_test.py $ARGS
           fi
 
+  benchmarks:
+    name: Run CodSpeed benchmarks
+    runs-on: ubuntu-24.04
+    needs:
+      - common
+      - determine-jobs
+    if: >-
+      (github.event_name == 'push' && github.ref_name == 'dev') ||
+      (github.event_name == 'pull_request' && needs.determine-jobs.outputs.benchmarks == 'true')
+    steps:
+      - name: Check out code from GitHub
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Restore Python
+        uses: ./.github/actions/restore-python
+        with:
+          python-version: ${{ env.DEFAULT_PYTHON }}
+          cache-key: ${{ needs.common.outputs.cache-key }}
+
+      - name: Build benchmarks
+        id: build
+        run: |
+          . venv/bin/activate
+          export BENCHMARK_LIB_CONFIG=$(python script/setup_codspeed_lib.py)
+          # --build-only prints BUILD_BINARY=<path> to stdout
+          BINARY=$(script/cpp_benchmark.py --all --build-only | grep '^BUILD_BINARY=' | tail -1 | cut -d= -f2-)
+          echo "binary=$BINARY" >> $GITHUB_OUTPUT
+
+      - name: Run CodSpeed benchmarks
+        uses: CodSpeedHQ/action@db35df748deb45fdef0960669f57d627c1956c30 # v4
+        with:
+          run: ${{ steps.build.outputs.binary }}
+          mode: simulation
+
   clang-tidy-single:
     name: ${{ matrix.name }}
     runs-on: ubuntu-24.04
@@ -335,14 +387,14 @@ jobs:
 
       - name: Cache platformio
         if: github.ref == 'refs/heads/dev'
-        uses: actions/cache@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
         with:
           path: ~/.platformio
           key: platformio-${{ matrix.pio_cache_key }}-${{ hashFiles('platformio.ini') }}
 
       - name: Cache platformio
         if: github.ref != 'refs/heads/dev'
-        uses: actions/cache/restore@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        uses: actions/cache/restore@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
         with:
           path: ~/.platformio
           key: platformio-${{ matrix.pio_cache_key }}-${{ hashFiles('platformio.ini') }}
@@ -414,14 +466,14 @@ jobs:
 
       - name: Cache platformio
         if: github.ref == 'refs/heads/dev'
-        uses: actions/cache@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
         with:
           path: ~/.platformio
           key: platformio-tidyesp32-${{ hashFiles('platformio.ini') }}
 
       - name: Cache platformio
         if: github.ref != 'refs/heads/dev'
-        uses: actions/cache/restore@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        uses: actions/cache/restore@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
         with:
           path: ~/.platformio
           key: platformio-tidyesp32-${{ hashFiles('platformio.ini') }}
@@ -503,14 +555,14 @@ jobs:
 
       - name: Cache platformio
         if: github.ref == 'refs/heads/dev'
-        uses: actions/cache@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
         with:
           path: ~/.platformio
           key: platformio-tidyesp32-${{ hashFiles('platformio.ini') }}
 
       - name: Cache platformio
         if: github.ref != 'refs/heads/dev'
-        uses: actions/cache/restore@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        uses: actions/cache/restore@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
         with:
           path: ~/.platformio
           key: platformio-tidyesp32-${{ hashFiles('platformio.ini') }}
@@ -671,7 +723,7 @@ jobs:
           cache-key: ${{ needs.common.outputs.cache-key }}
       - uses: esphome/pre-commit-action@43cd1109c09c544d97196f7730ee5b2e0cc6d81e # v3.0.1 fork with pinned actions/cache
         env:
-          SKIP: pylint,clang-tidy-hash
+          SKIP: pylint,clang-tidy-hash,ci-custom
       - uses: pre-commit-ci/lite-action@5d6cc0eb514c891a40562a58a8e71576c5c7fb43 # v1.1.0
         if: always()
 
@@ -765,7 +817,7 @@ jobs:
       - name: Restore cached memory analysis
         id: cache-memory-analysis
         if: steps.check-script.outputs.skip != 'true' && steps.check-tests.outputs.skip != 'true'
-        uses: actions/cache/restore@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        uses: actions/cache/restore@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
         with:
           path: memory-analysis-target.json
           key: ${{ steps.cache-key.outputs.cache-key }}
@@ -789,7 +841,7 @@ jobs:
 
       - name: Cache platformio
         if: steps.check-script.outputs.skip != 'true' && steps.check-tests.outputs.skip != 'true' && steps.cache-memory-analysis.outputs.cache-hit != 'true'
-        uses: actions/cache/restore@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        uses: actions/cache/restore@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
         with:
           path: ~/.platformio
           key: platformio-memory-${{ fromJSON(needs.determine-jobs.outputs.memory_impact).platform }}-${{ hashFiles('platformio.ini') }}
@@ -830,7 +882,7 @@ jobs:
 
       - name: Save memory analysis to cache
         if: steps.check-script.outputs.skip != 'true' && steps.check-tests.outputs.skip != 'true' && steps.cache-memory-analysis.outputs.cache-hit != 'true' && steps.build.outcome == 'success'
-        uses: actions/cache/save@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        uses: actions/cache/save@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
         with:
           path: memory-analysis-target.json
           key: ${{ steps.cache-key.outputs.cache-key }}
@@ -877,7 +929,7 @@ jobs:
           python-version: ${{ env.DEFAULT_PYTHON }}
           cache-key: ${{ needs.common.outputs.cache-key }}
       - name: Cache platformio
-        uses: actions/cache/restore@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5.0.3
+        uses: actions/cache/restore@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
         with:
           path: ~/.platformio
           key: platformio-memory-${{ fromJSON(needs.determine-jobs.outputs.memory_impact).platform }}-${{ hashFiles('platformio.ini') }}
@@ -945,13 +997,13 @@ jobs:
           python-version: ${{ env.DEFAULT_PYTHON }}
           cache-key: ${{ needs.common.outputs.cache-key }}
       - name: Download target analysis JSON
-        uses: actions/download-artifact@70fc10c6e5e1ce46ad2ea6f2b72d43f7d47b13c3 # v8.0.0
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
         with:
           name: memory-analysis-target
           path: ./memory-analysis
         continue-on-error: true
       - name: Download PR analysis JSON
-        uses: actions/download-artifact@70fc10c6e5e1ce46ad2ea6f2b72d43f7d47b13c3 # v8.0.0
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
         with:
           name: memory-analysis-pr
           path: ./memory-analysis

.github/workflows/codeowner-approved-label-update.yml

@@ -10,6 +10,9 @@ name: Codeowner Approved Label
 on:
   pull_request_target:
     types: [opened, synchronize, reopened, ready_for_review]
+    branches-ignore:
+      - release
+      - beta
 
 permissions:
   issues: write

.github/workflows/codeowner-review-request.yml

@@ -13,6 +13,9 @@ on:
   # Needs to be pull_request_target to get write permissions
   pull_request_target:
     types: [opened, reopened, synchronize, ready_for_review]
+    branches-ignore:
+      - release
+      - beta
 
 permissions:
   pull-requests: write

.github/workflows/codeql.yml

@@ -58,7 +58,7 @@ jobs:
 
       # Initializes the CodeQL tools for scanning.
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@0d579ffd059c29b07949a3cce3983f0780820c98 # v4.32.6
+        uses: github/codeql-action/init@c10b8064de6f491fea524254123dbe5e09572f13 # v4.35.1
         with:
           languages: ${{ matrix.language }}
           build-mode: ${{ matrix.build-mode }}
@@ -86,6 +86,6 @@ jobs:
           exit 1
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@0d579ffd059c29b07949a3cce3983f0780820c98 # v4.32.6
+        uses: github/codeql-action/analyze@c10b8064de6f491fea524254123dbe5e09572f13 # v4.35.1
         with:
           category: "/language:${{matrix.language}}"

.github/workflows/pr-title-check.yml

@@ -3,6 +3,9 @@ name: PR Title Check
 on:
   pull_request:
     types: [opened, edited, synchronize, reopened]
+    branches-ignore:
+      - release
+      - beta
 
 permissions:
   contents: read
@@ -65,6 +68,18 @@ jobs:
               return;
             }
 
+            // Check for angle brackets not wrapped in backticks.
+            // Astro docs MDX treats bare < as JSX component opening tags.
+            const stripped = title.replace(/`[^`]*`/g, '');
+            if (/[<>]/.test(stripped)) {
+              core.setFailed(
+                'PR title contains `<` or `>` not wrapped in backticks.\n' +
+                'Astro docs MDX interprets bare `<` as JSX components.\n' +
+                'Please wrap angle brackets with backticks, e.g.: [component] Add `<feature>` support'
+              );
+              return;
+            }
+
             // Check title starts with [tag] prefix
             const bracketPattern = /^\[\w+\]/;
             if (!bracketPattern.test(title)) {

.github/workflows/release.yml

@@ -70,7 +70,7 @@ jobs:
           pip3 install build
           python3 -m build
       - name: Publish
-        uses: pypa/gh-action-pypi-publish@ed0c53931b1dc9bd32cbe73a98c7f6766f8a527e # v1.13.0
+        uses: pypa/gh-action-pypi-publish@cef221092ed1bacb1cc03d23a2d87d1d172e277b # v1.14.0
         with:
           skip-existing: true
 
@@ -102,12 +102,12 @@ jobs:
         uses: docker/setup-buildx-action@4d04d5d9486b7bd6fa91e7baf45bbb4f8b9deedd # v4.0.0
 
       - name: Log in to docker hub
-        uses: docker/login-action@b45d80f862d83dbcd57f89517bcf500b2ab88fb2 # v4.0.0
+        uses: docker/login-action@4907a6ddec9925e35a0a9e82d7399ccc52663121 # v4.1.0
         with:
           username: ${{ secrets.DOCKER_USER }}
           password: ${{ secrets.DOCKER_PASSWORD }}
       - name: Log in to the GitHub container registry
-        uses: docker/login-action@b45d80f862d83dbcd57f89517bcf500b2ab88fb2 # v4.0.0
+        uses: docker/login-action@4907a6ddec9925e35a0a9e82d7399ccc52663121 # v4.1.0
         with:
           registry: ghcr.io
           username: ${{ github.actor }}
@@ -171,7 +171,7 @@ jobs:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
       - name: Download digests
-        uses: actions/download-artifact@70fc10c6e5e1ce46ad2ea6f2b72d43f7d47b13c3 # v8.0.0
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
         with:
           pattern: digests-*
           path: /tmp/digests
@@ -182,13 +182,13 @@ jobs:
 
       - name: Log in to docker hub
         if: matrix.registry == 'dockerhub'
-        uses: docker/login-action@b45d80f862d83dbcd57f89517bcf500b2ab88fb2 # v4.0.0
+        uses: docker/login-action@4907a6ddec9925e35a0a9e82d7399ccc52663121 # v4.1.0
         with:
           username: ${{ secrets.DOCKER_USER }}
           password: ${{ secrets.DOCKER_PASSWORD }}
       - name: Log in to the GitHub container registry
         if: matrix.registry == 'ghcr'
-        uses: docker/login-action@b45d80f862d83dbcd57f89517bcf500b2ab88fb2 # v4.0.0
+        uses: docker/login-action@4907a6ddec9925e35a0a9e82d7399ccc52663121 # v4.1.0
         with:
           registry: ghcr.io
           username: ${{ github.actor }}
@@ -221,7 +221,7 @@ jobs:
     steps:
       - name: Generate a token
         id: generate-token
-        uses: actions/create-github-app-token@29824e69f54612133e76f7eaac726eef6c875baf # v2.2.1
+        uses: actions/create-github-app-token@f8d387b68d61c58ab83c6c016672934102569859 # v3.0.0
         with:
           app-id: ${{ secrets.ESPHOME_GITHUB_APP_ID }}
           private-key: ${{ secrets.ESPHOME_GITHUB_APP_PRIVATE_KEY }}
@@ -256,7 +256,7 @@ jobs:
     steps:
       - name: Generate a token
         id: generate-token
-        uses: actions/create-github-app-token@29824e69f54612133e76f7eaac726eef6c875baf # v2.2.1
+        uses: actions/create-github-app-token@f8d387b68d61c58ab83c6c016672934102569859 # v3.0.0
         with:
           app-id: ${{ secrets.ESPHOME_GITHUB_APP_ID }}
           private-key: ${{ secrets.ESPHOME_GITHUB_APP_PRIVATE_KEY }}
@@ -287,7 +287,7 @@ jobs:
     steps:
       - name: Generate a token
         id: generate-token
-        uses: actions/create-github-app-token@29824e69f54612133e76f7eaac726eef6c875baf # v2.2.1
+        uses: actions/create-github-app-token@f8d387b68d61c58ab83c6c016672934102569859 # v3.0.0
         with:
           app-id: ${{ secrets.ESPHOME_GITHUB_APP_ID }}
           private-key: ${{ secrets.ESPHOME_GITHUB_APP_PRIVATE_KEY }}

.github/workflows/sync-device-classes.yml

@@ -24,7 +24,7 @@ jobs:
       - name: Setup Python
         uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
-          python-version: 3.13
+          python-version: "3.14"
 
       - name: Install Home Assistant
         run: |

.pre-commit-config.yaml

@@ -11,7 +11,7 @@ ci:
 repos:
   - repo: https://github.com/astral-sh/ruff-pre-commit
     # Ruff version.
-    rev: v0.15.5
+    rev: v0.15.9
     hooks:
       # Run the linter.
       - id: ruff
@@ -65,3 +65,7 @@ repos:
         files: ^(\.clang-tidy|platformio\.ini|requirements_dev\.txt)$
         pass_filenames: false
         additional_dependencies: []
+      - id: ci-custom
+        name: ci-custom
+        entry: python3 script/run-in-env.py script/ci-custom.py
+        language: system

CODEOWNERS

@@ -92,6 +92,7 @@ esphome/components/bmp3xx_i2c/* @latonita
 esphome/components/bmp3xx_spi/* @latonita
 esphome/components/bmp581_base/* @danielkent-net @kahrendt
 esphome/components/bmp581_i2c/* @danielkent-net @kahrendt
+esphome/components/bmp581_spi/* @danielkent-net @kahrendt
 esphome/components/bp1658cj/* @Cossid
 esphome/components/bp5758d/* @Cossid
 esphome/components/bthome_mithermometer/* @nagyrobi
@@ -141,12 +142,13 @@ esphome/components/dlms_meter/* @SimonFischer04
 esphome/components/dps310/* @kbx81
 esphome/components/ds1307/* @badbadc0ffee
 esphome/components/ds2484/* @mrk-its
-esphome/components/dsmr/* @glmnet @PolarGoose @zuidwijk
+esphome/components/dsmr/* @glmnet @PolarGoose
 esphome/components/duty_time/* @dudanov
 esphome/components/ee895/* @Stock-M
 esphome/components/ektf2232/touchscreen/* @jesserockz
 esphome/components/emc2101/* @ellull
 esphome/components/emmeti/* @E440QF
+esphome/components/emontx/* @FredM67 @glynhudson @TrystanLea
 esphome/components/ens160/* @latonita
 esphome/components/ens160_base/* @latonita @vincentscode
 esphome/components/ens160_i2c/* @latonita
@@ -216,6 +218,7 @@ esphome/components/hbridge/light/* @DotNetDann
 esphome/components/hbridge/switch/* @dwmw2
 esphome/components/hc8/* @omartijn
 esphome/components/hdc2010/* @optimusprimespace @ssieb
+esphome/components/hdc2080/* @G-Pereira @jesserockz
 esphome/components/hdc302x/* @joshuasing
 esphome/components/he60r/* @clydebarrow
 esphome/components/heatpumpir/* @rob-deutsch
@@ -244,7 +247,6 @@ esphome/components/hyt271/* @Philippe12
 esphome/components/i2c/* @esphome/core
 esphome/components/i2c_device/* @gabest11
 esphome/components/i2s_audio/* @jesserockz
-esphome/components/i2s_audio/media_player/* @jesserockz
 esphome/components/i2s_audio/microphone/* @jesserockz
 esphome/components/i2s_audio/speaker/* @jesserockz @kahrendt
 esphome/components/iaqcore/* @yozik04
@@ -330,6 +332,7 @@ esphome/components/mipi_dsi/* @clydebarrow
 esphome/components/mipi_rgb/* @clydebarrow
 esphome/components/mipi_spi/* @clydebarrow
 esphome/components/mitsubishi/* @RubyBailey
+esphome/components/mitsubishi_cn105/* @crnjan
 esphome/components/mixer/speaker/* @kahrendt
 esphome/components/mlx90393/* @functionpointer
 esphome/components/mlx90614/* @jesserockz
@@ -458,6 +461,9 @@ esphome/components/sn74hc165/* @jesserockz
 esphome/components/socket/* @esphome/core
 esphome/components/sonoff_d1/* @anatoly-savchenkov
 esphome/components/sound_level/* @kahrendt
+esphome/components/spa06_base/* @danielkent-net
+esphome/components/spa06_i2c/* @danielkent-net
+esphome/components/spa06_spi/* @danielkent-net
 esphome/components/speaker/* @jesserockz @kahrendt
 esphome/components/speaker/media_player/* @kahrendt @synesthesiam
 esphome/components/speaker_source/* @kahrendt

Doxyfile

@@ -48,7 +48,7 @@ PROJECT_NAME           = ESPHome
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 2026.3.3
+PROJECT_NUMBER         = 2026.4.0b1
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a

README.md

@@ -1,4 +1,4 @@
-# ESPHome [![Discord Chat](https://img.shields.io/discord/429907082951524364.svg)](https://discord.gg/KhAMKrd) [![GitHub release](https://img.shields.io/github/release/esphome/esphome.svg)](https://GitHub.com/esphome/esphome/releases/)
+# ESPHome [![Discord Chat](https://img.shields.io/discord/429907082951524364.svg)](https://discord.gg/KhAMKrd) [![GitHub release](https://img.shields.io/github/release/esphome/esphome.svg)](https://GitHub.com/esphome/esphome/releases/) [![CodSpeed](https://img.shields.io/endpoint?url=https://codspeed.io/badge.json)](https://codspeed.io/esphome/esphome)
 
 <a href="https://esphome.io/">
   <picture>

esphome/__main__.py

@@ -1046,7 +1046,11 @@ def show_logs(config: ConfigType, args: ArgsProtocol, devices: list[str]) -> int
     ):
         from esphome.components.api.client import run_logs
 
-        return run_logs(config, network_devices)
+        return run_logs(
+            config,
+            network_devices,
+            subscribe_states=not getattr(args, "no_states", False),
+        )
 
     if port_type in (PortType.NETWORK, PortType.MQTT) and has_mqtt_logging():
         from esphome import mqtt
@@ -1079,7 +1083,7 @@ def command_config(args: ArgsProtocol, config: ConfigType) -> int | None:
     # add the console decoration so the front-end can hide the secrets
     if not args.show_secrets:
         output = re.sub(
-            r"(password|key|psk|ssid)\: (.+)", r"\1: \\033[5m\2\\033[6m", output
+            r"(password|key|psk|ssid)\: (.+)", r"\1: \\033[8m\2\\033[28m", output
         )
     if not CORE.quiet:
         safe_print(output)
@@ -1238,6 +1242,38 @@ def command_clean(args: ArgsProtocol, config: ConfigType) -> int | None:
     return 0
 
 
+def command_bundle(args: ArgsProtocol, config: ConfigType) -> int | None:
+    from esphome.bundle import BUNDLE_EXTENSION, ConfigBundleCreator
+
+    creator = ConfigBundleCreator(config)
+
+    if args.list_only:
+        files = creator.discover_files()
+        for bf in sorted(files, key=lambda f: f.path):
+            safe_print(f"  {bf.path}")
+        _LOGGER.info("Found %d files", len(files))
+        return 0
+
+    result = creator.create_bundle()
+
+    if args.output:
+        output_path = Path(args.output)
+    else:
+        stem = CORE.config_path.stem
+        output_path = CORE.config_dir / f"{stem}{BUNDLE_EXTENSION}"
+
+    output_path.parent.mkdir(parents=True, exist_ok=True)
+    output_path.write_bytes(result.data)
+
+    _LOGGER.info(
+        "Bundle created: %s (%d files, %.1f KB)",
+        output_path,
+        len(result.files),
+        len(result.data) / 1024,
+    )
+    return 0
+
+
 def command_dashboard(args: ArgsProtocol) -> int | None:
     from esphome.dashboard import dashboard
 
@@ -1513,6 +1549,7 @@ POST_CONFIG_ACTIONS = {
     "rename": command_rename,
     "discover": command_discover,
     "analyze-memory": command_analyze_memory,
+    "bundle": command_bundle,
 }
 
 SIMPLE_CONFIG_ACTIONS = [
@@ -1664,6 +1701,11 @@ def parse_args(argv):
         help="Reset the device before starting serial logs.",
         default=os.getenv("ESPHOME_SERIAL_LOGGING_RESET"),
     )
+    parser_logs.add_argument(
+        "--no-states",
+        action="store_true",
+        help="Do not show entity state changes in log output.",
+    )
 
     parser_discover = subparsers.add_parser(
         "discover",
@@ -1809,6 +1851,24 @@ def parse_args(argv):
         "configuration", help="Your YAML configuration file(s).", nargs="+"
     )
 
+    parser_bundle = subparsers.add_parser(
+        "bundle",
+        help="Create a self-contained config bundle for remote compilation.",
+    )
+    parser_bundle.add_argument(
+        "configuration", help="Your YAML configuration file(s).", nargs="+"
+    )
+    parser_bundle.add_argument(
+        "-o",
+        "--output",
+        help="Output path for the bundle archive.",
+    )
+    parser_bundle.add_argument(
+        "--list-only",
+        help="List discovered files without creating the archive.",
+        action="store_true",
+    )
+
     # Keep backward compatibility with the old command line format of
     # esphome <config> <command>.
     #
@@ -1887,6 +1947,16 @@ def run_esphome(argv):
         _LOGGER.warning("Skipping secrets file %s", conf_path)
         return 0
 
+    # Bundle support: if the configuration is a .esphomebundle, extract it
+    # and rewrite conf_path to the extracted YAML config.
+    from esphome.bundle import is_bundle_path, prepare_bundle_for_compile
+
+    if is_bundle_path(conf_path):
+        _LOGGER.info("Extracting config bundle %s...", conf_path)
+        conf_path = prepare_bundle_for_compile(conf_path)
+        # Update the argument so downstream code sees the extracted path
+        args.configuration[0] = str(conf_path)
+
     CORE.config_path = conf_path
     CORE.dashboard = args.dashboard
 

esphome/analyze_memory/__init__.py

@@ -1,6 +1,6 @@
 """Memory usage analyzer for ESPHome compiled binaries."""
 
-from collections import defaultdict
+from collections import Counter, defaultdict
 from dataclasses import dataclass, field
 import logging
 from pathlib import Path
@@ -40,6 +40,15 @@ _READELF_SECTION_PATTERN = re.compile(
     r"\s*\[\s*\d+\]\s+([\.\w]+)\s+\w+\s+[\da-fA-F]+\s+[\da-fA-F]+\s+([\da-fA-F]+)"
 )
 
+# Regex for extracting call targets from objdump disassembly
+# Matches direct call instructions across architectures:
+#   Xtensa: call0/call4/call8/call12/callx0/callx4/callx8/callx12 <addr> <symbol>
+#   ARM:    bl/blx <addr> <symbol>
+# Captures the mangled symbol name inside angle brackets.
+_CALL_TARGET_PATTERN = re.compile(
+    r"\t(?:call(?:0|4|8|12)|callx(?:0|4|8|12)|blx?)\s+[\da-fA-F]+ <([^>]+)>"
+)
+
 # Component category prefixes
 _COMPONENT_PREFIX_ESPHOME = "[esphome]"
 _COMPONENT_PREFIX_EXTERNAL = "[external]"
@@ -47,6 +56,10 @@ _COMPONENT_PREFIX_LIB = "[lib]"
 _COMPONENT_CORE = f"{_COMPONENT_PREFIX_ESPHOME}core"
 _COMPONENT_API = f"{_COMPONENT_PREFIX_ESPHOME}api"
 
+# Placement new storage suffix (generated by codegen Pvariable)
+_PSTORAGE_SUFFIX = "__pstorage"
+
+
 # C++ namespace prefixes
 _NAMESPACE_ESPHOME = "esphome::"
 _NAMESPACE_STD = "std::"
@@ -192,20 +205,27 @@ class MemoryAnalyzer:
         self._cswtch_symbols: list[tuple[str, int, str, str]] = []
         # Library symbol mapping: symbol_name -> library_name
         self._lib_symbol_map: dict[str, str] = {}
+        # Source file symbol mapping: symbol_name -> component_name
+        # Used for extern "C" and other symbols without C++ namespace
+        self._source_symbol_map: dict[str, str] = {}
         # Library dir to name mapping: "lib641" -> "espsoftwareserial",
         # "espressif__mdns" -> "mdns"
         self._lib_hash_to_name: dict[str, str] = {}
         # Heuristic category to library redirect: "mdns_lib" -> "[lib]mdns"
         self._heuristic_to_lib: dict[str, str] = {}
+        # Function call counts: mangled_name -> call_count
+        self._function_call_counts: Counter[str] = Counter()
 
     def analyze(self) -> dict[str, ComponentMemory]:
         """Analyze the ELF file and return component memory usage."""
         self._parse_sections()
         self._parse_symbols()
         self._scan_libraries()
+        self._scan_source_symbols()
         self._categorize_symbols()
         self._analyze_cswtch_symbols()
         self._analyze_sdk_libraries()
+        self._analyze_function_calls()
         return dict(self.components)
 
     def _parse_sections(self) -> None:
@@ -316,6 +336,13 @@ class MemoryAnalyzer:
         # Demangle C++ names if needed
         demangled = self._demangle_symbol(symbol_name)
 
+        # Check for placement new storage symbols (generated by codegen)
+        # Format: {component}__{id}__pstorage
+        if demangled.endswith(_PSTORAGE_SUFFIX) and (
+            component := self._match_pstorage_component(demangled)
+        ):
+            return component
+
         # Check for special component classes first (before namespace pattern)
         # This handles cases like esphome::ESPHomeOTAComponent which should map to ota
         if _NAMESPACE_ESPHOME in demangled:
@@ -351,6 +378,11 @@ class MemoryAnalyzer:
         if lib_name := self._lib_symbol_map.get(symbol_name):
             return f"{_COMPONENT_PREFIX_LIB}{lib_name}"
 
+        # Check source file mapping (catches extern "C" functions in ESPHome sources)
+        # Must be before heuristic patterns since source attribution is authoritative
+        if component := self._source_symbol_map.get(symbol_name):
+            return component
+
         # Check against symbol patterns
         for component, patterns in SYMBOL_PATTERNS.items():
             if any(pattern in symbol_name for pattern in patterns):
@@ -378,14 +410,33 @@ class MemoryAnalyzer:
         # Track uncategorized symbols for analysis
         return "other"
 
+    def _match_pstorage_component(self, symbol_name: str) -> str | None:
+        """Match a __pstorage symbol to its ESPHome component.
+
+        Symbol format: {component}__{id}__pstorage
+        The component namespace is embedded by codegen before the double underscore.
+        """
+        prefix = symbol_name[: -len(_PSTORAGE_SUFFIX)]
+        # Extract component namespace before the first double underscore
+        dunder_pos = prefix.find("__")
+        if dunder_pos == -1:
+            return None
+        component_name = prefix[:dunder_pos]
+        if component_name in get_esphome_components():
+            return f"{_COMPONENT_PREFIX_ESPHOME}{component_name}"
+        if component_name in self.external_components:
+            return f"{_COMPONENT_PREFIX_EXTERNAL}{component_name}"
+        return None
+
     def _batch_demangle_symbols(self, symbols: list[str]) -> None:
         """Batch demangle C++ symbol names for efficiency."""
         if not symbols:
             return
 
         _LOGGER.info("Demangling %d symbols", len(symbols))
-        self._demangle_cache = batch_demangle(symbols, objdump_path=self.objdump_path)
-        _LOGGER.info("Successfully demangled %d symbols", len(self._demangle_cache))
+        demangled = batch_demangle(symbols, objdump_path=self.objdump_path)
+        self._demangle_cache.update(demangled)
+        _LOGGER.info("Successfully demangled %d symbols", len(demangled))
 
     def _demangle_symbol(self, symbol: str) -> str:
         """Get demangled C++ symbol name from cache."""
@@ -640,6 +691,7 @@ class MemoryAnalyzer:
             return None
 
         symbol_map: dict[str, str] = {}
+        source_symbol_map: dict[str, str] = {}
         current_symbol: str | None = None
         section_prefixes = (".text.", ".rodata.", ".data.", ".bss.", ".literal.")
 
@@ -675,9 +727,18 @@ class MemoryAnalyzer:
                     if dir_key in source_path:
                         symbol_map[current_symbol] = lib_name
                         break
+                else:
+                    # Map ESPHome source files to components for extern "C"
+                    # and other symbols without C++ namespace
+                    component = self._source_file_to_component(source_path)
+                    if component.startswith(
+                        (_COMPONENT_PREFIX_ESPHOME, _COMPONENT_PREFIX_EXTERNAL)
+                    ):
+                        source_symbol_map[current_symbol] = component
 
             current_symbol = None
 
+        self._source_symbol_map = source_symbol_map
         return symbol_map or None
 
     def _scan_libraries(self) -> None:
@@ -728,6 +789,112 @@ class MemoryAnalyzer:
             len(libraries),
         )
 
+    def _scan_source_symbols(self) -> None:
+        """Scan ESPHome source object files to map extern "C" symbols to components.
+
+        When no linker map file is available, this uses ``nm`` to scan ``.o`` files
+        under ``src/esphome/`` and build a symbol-to-component mapping. This catches
+        ``extern "C"`` functions and other symbols that lack C++ namespace prefixes.
+
+        Skips scanning if ``_source_symbol_map`` was already populated by
+        ``_parse_map_file()``.
+        """
+        if self._source_symbol_map or not self.nm_path:
+            return
+
+        obj_dir = self._find_object_files_dir()
+        if obj_dir is None:
+            return
+
+        # Find ESPHome source object files
+        esphome_src_dir = obj_dir / "src" / "esphome"
+        if not esphome_src_dir.is_dir():
+            return
+
+        obj_files = sorted(esphome_src_dir.rglob("*.o"))
+        if not obj_files:
+            return
+
+        # Run nm with --print-file-name to get file:symbol mapping
+        result = run_tool(
+            [self.nm_path, "--print-file-name", "-g", "--defined-only"]
+            + [str(f) for f in obj_files],
+        )
+        if result is None or result.returncode != 0:
+            _LOGGER.debug("nm scan of source objects failed")
+            return
+
+        self._source_symbol_map = self._parse_nm_source_output(result.stdout, obj_dir)
+        if self._source_symbol_map:
+            _LOGGER.info(
+                "Built source symbol map from nm: %d symbols",
+                len(self._source_symbol_map),
+            )
+
+    def _parse_nm_source_output(self, output: str, base_dir: Path) -> dict[str, str]:
+        """Parse nm output to map non-namespaced symbols to ESPHome components.
+
+        Extracts global defined symbols from ESPHome source object files that
+        don't use C++ namespacing (e.g. ``extern "C"`` functions).
+
+        Args:
+            output: Raw stdout from ``nm --print-file-name -g --defined-only``
+                or ``nm --print-file-name -S``.
+            base_dir: Build directory for computing relative paths.
+
+        Returns:
+            Dict mapping symbol names to component names.
+        """
+        source_map: dict[str, str] = {}
+        for line in output.splitlines():
+            # Format: /path/to/file.o: addr type name
+            #     or: /path/to/file.o: addr size type name (with -S)
+            colon_idx = line.rfind(".o:")
+            if colon_idx == -1:
+                continue
+
+            file_path = line[: colon_idx + 2]
+            fields = line[colon_idx + 3 :].split()
+            if len(fields) < 3:
+                continue
+
+            # With -S flag, format is: addr size type name
+            # Without -S flag: addr type name
+            # type is a single char; size is hex digits
+            # Detect by checking if fields[1] is a single uppercase letter (type)
+            if len(fields[1]) == 1 and fields[1].isalpha():
+                # addr type name
+                sym_type = fields[1]
+                symbol_name = fields[2]
+            elif len(fields) >= 4:
+                # addr size type name
+                sym_type = fields[2]
+                symbol_name = fields[3]
+            else:
+                continue
+
+            # Only global defined symbols (uppercase type)
+            if not sym_type.isupper() or sym_type == "U":
+                continue
+
+            # Skip symbols already in esphome:: namespace
+            if symbol_name.startswith("_ZN7esphome"):
+                continue
+
+            # Make path relative to base_dir for _source_file_to_component
+            try:
+                rel_path = str(Path(file_path).relative_to(base_dir))
+            except ValueError:
+                continue
+
+            component = self._source_file_to_component(rel_path)
+            if component.startswith(
+                (_COMPONENT_PREFIX_ESPHOME, _COMPONENT_PREFIX_EXTERNAL)
+            ):
+                source_map[symbol_name] = component
+
+        return source_map
+
     def _find_object_files_dir(self) -> Path | None:
         """Find the directory containing object files for this build.
 
@@ -1011,6 +1178,43 @@ class MemoryAnalyzer:
             total_size,
         )
 
+    def _analyze_function_calls(self) -> None:
+        """Count function call sites by parsing disassembly output.
+
+        Parses direct call instructions (call0/call8/bl/blx) from objdump -d
+        to count how many times each function is called. This helps identify
+        inlining candidates — frequently called small functions benefit most
+        from inlining.
+        """
+        result = run_tool(
+            [self.objdump_path, "-d", str(self.elf_path)],
+            timeout=60,
+        )
+        if result is None or result.returncode != 0:
+            _LOGGER.debug("Failed to disassemble ELF for function call analysis")
+            return
+
+        self._function_call_counts = Counter(
+            match.group(1)
+            for line in result.stdout.splitlines()
+            if (match := _CALL_TARGET_PATTERN.search(line))
+        )
+
+        # Demangle any call targets not already in the cache
+        missing = [
+            name
+            for name in self._function_call_counts
+            if name not in self._demangle_cache
+        ]
+        if missing:
+            self._batch_demangle_symbols(missing)
+
+        _LOGGER.debug(
+            "Function call analysis: %d unique targets, %d total calls",
+            len(self._function_call_counts),
+            sum(self._function_call_counts.values()),
+        )
+
     def get_unattributed_ram(self) -> tuple[int, int, int]:
         """Get unattributed RAM sizes (SDK/framework overhead).
 

esphome/analyze_memory/cli.py

@@ -15,6 +15,7 @@ from . import (
     _COMPONENT_PREFIX_ESPHOME,
     _COMPONENT_PREFIX_EXTERNAL,
     _COMPONENT_PREFIX_LIB,
+    _PSTORAGE_SUFFIX,
     RAM_SECTIONS,
     MemoryAnalyzer,
 )
@@ -23,6 +24,17 @@ if TYPE_CHECKING:
     from . import ComponentMemory
 
 
+def _format_pstorage_name(name: str) -> str:
+    """Format a __pstorage symbol as 'storage for {id}'."""
+    if not name.endswith(_PSTORAGE_SUFFIX):
+        return name
+    prefix = name[: -len(_PSTORAGE_SUFFIX)]
+    # Strip component namespace prefix: {component}__{id} -> {id}
+    dunder_pos = prefix.find("__")
+    var_id = prefix[dunder_pos + 2 :] if dunder_pos != -1 else prefix
+    return f"storage for {var_id}"
+
+
 class MemoryAnalyzerCLI(MemoryAnalyzer):
     """Memory analyzer with CLI-specific report generation."""
 
@@ -148,11 +160,14 @@ class MemoryAnalyzerCLI(MemoryAnalyzer):
         If section is one of the RAM sections (.data or .bss), a label like
         " [data]" or " [bss]" is appended. For non-RAM sections or when
         section is None, no section label is added.
+
+        Placement new storage symbols are formatted as "storage for {id}".
         """
+        display_name = _format_pstorage_name(demangled)
         section_label = ""
         if section in RAM_SECTIONS:
             section_label = f" [{section[1:]}]"  # .data -> [data], .bss -> [bss]
-        return f"{demangled} ({size:,} B){section_label}"
+        return f"{display_name} ({size:,} B){section_label}"
 
     def _add_top_symbols(self, lines: list[str]) -> None:
         """Add a section showing the top largest symbols in the binary."""
@@ -175,11 +190,13 @@ class MemoryAnalyzerCLI(MemoryAnalyzer):
         for i, (_, demangled, size, section, component) in enumerate(top_symbols):
             # Format section label
             section_label = f"[{section[1:]}]" if section else ""
-            # Truncate demangled name if too long
+            # Format storage symbols readably
+            display_name = _format_pstorage_name(demangled)
+            # Truncate if too long
             demangled_display = (
-                f"{demangled[:truncate_limit]}..."
-                if len(demangled) > self.COL_TOP_SYMBOL_NAME
-                else demangled
+                f"{display_name[:truncate_limit]}..."
+                if len(display_name) > self.COL_TOP_SYMBOL_NAME
+                else display_name
             )
             lines.append(
                 f"{i + 1:>2}. {size:>7,} B {section_label:<8} {demangled_display:<{self.COL_TOP_SYMBOL_NAME}} {component}"
@@ -231,6 +248,110 @@ class MemoryAnalyzerCLI(MemoryAnalyzer):
                     lines.append(f"    {size:>6,} B  {sym_name}")
             lines.append("")
 
+    # Number of top called functions to show
+    TOP_CALLS_LIMIT: int = 50
+    # Number of inlining candidates to show
+    INLINE_CANDIDATES_LIMIT: int = 25
+    # Maximum function size in bytes to consider for inlining
+    INLINE_SIZE_THRESHOLD: int = 16
+
+    def _build_symbol_sizes(self) -> dict[str, int]:
+        """Build a size lookup from all component symbols: mangled_name -> size."""
+        return {
+            symbol: size
+            for symbols in self._component_symbols.values()
+            for symbol, _, size, _ in symbols
+        }
+
+    def _format_call_row(
+        self, index: int, mangled: str, count: int, symbol_sizes: dict[str, int]
+    ) -> str:
+        """Format a single row for call frequency tables."""
+        demangled = self._demangle_cache.get(mangled, mangled)
+        if len(demangled) > 80:
+            demangled = f"{demangled[:77]}..."
+        size = symbol_sizes.get(mangled)
+        size_str = f"{size:>5,} B" if size is not None else "      ?"
+        return f"{index:>3}  {count:>5}  {size_str}  {demangled}"
+
+    def _add_call_table_header(self, lines: list[str]) -> None:
+        """Add the header row for call frequency tables."""
+        lines.append(f"{'#':>3}  {'Calls':>5}  {'Size':>7}  Function")
+        lines.append(f"{'---':>3}  {'-----':>5}  {'-------':>7}  {'-' * 60}")
+
+    def _add_function_call_analysis(self, lines: list[str]) -> None:
+        """Add function call frequency analysis section.
+
+        Shows the most frequently called functions by call site count.
+        """
+        self._add_section_header(lines, "Top Called Functions")
+
+        symbol_sizes = self._build_symbol_sizes()
+
+        # Sort by call count descending
+        sorted_calls = sorted(
+            self._function_call_counts.items(), key=lambda x: x[1], reverse=True
+        )
+
+        self._add_call_table_header(lines)
+
+        for i, (mangled, count) in enumerate(sorted_calls[: self.TOP_CALLS_LIMIT]):
+            lines.append(self._format_call_row(i + 1, mangled, count, symbol_sizes))
+
+        total_calls = sum(self._function_call_counts.values())
+        lines.append("")
+        lines.append(
+            f"Total: {len(self._function_call_counts)} unique targets, "
+            f"{total_calls:,} call sites"
+        )
+        lines.append("")
+
+    def _add_inline_candidates(self, lines: list[str]) -> None:
+        """Add inlining candidates section.
+
+        Shows frequently called functions that are small enough to benefit
+        from inlining (< 16 bytes). These are the best candidates for
+        reducing call overhead.
+        """
+        self._add_section_header(
+            lines,
+            f"Inlining Candidates (<{self.INLINE_SIZE_THRESHOLD} B, by call count)",
+        )
+
+        symbol_sizes = self._build_symbol_sizes()
+
+        # Filter to small functions with known size, sort by call count
+        candidates = sorted(
+            (
+                (mangled, count)
+                for mangled, count in self._function_call_counts.items()
+                if mangled in symbol_sizes
+                and symbol_sizes[mangled] < self.INLINE_SIZE_THRESHOLD
+            ),
+            key=lambda x: x[1],
+            reverse=True,
+        )
+
+        if not candidates:
+            lines.append("No candidates found.")
+            lines.append("")
+            return
+
+        self._add_call_table_header(lines)
+
+        for i, (mangled, count) in enumerate(
+            candidates[: self.INLINE_CANDIDATES_LIMIT]
+        ):
+            lines.append(self._format_call_row(i + 1, mangled, count, symbol_sizes))
+
+        lines.append("")
+        lines.append(
+            f"Showing top {min(len(candidates), self.INLINE_CANDIDATES_LIMIT)} "
+            f"of {len(candidates)} functions under "
+            f"{self.INLINE_SIZE_THRESHOLD} B"
+        )
+        lines.append("")
+
     def generate_report(self, detailed: bool = False) -> str:
         """Generate a formatted memory report."""
         components = sorted(
@@ -469,15 +590,16 @@ class MemoryAnalyzerCLI(MemoryAnalyzer):
                 lines.append(f"Total size: {comp_mem.flash_total:,} B")
                 lines.append("")
 
-                # Show all symbols above threshold for better visibility
+                # Show symbols above threshold, always include storage symbols
                 large_symbols = [
                     (sym, dem, size, sec)
                     for sym, dem, size, sec in sorted_symbols
                     if size > self.SYMBOL_SIZE_THRESHOLD
+                    or dem.endswith(_PSTORAGE_SUFFIX)
                 ]
 
                 lines.append(
-                    f"{comp_name} Symbols > {self.SYMBOL_SIZE_THRESHOLD} B ({len(large_symbols)} symbols):"
+                    f"{comp_name} Symbols > {self.SYMBOL_SIZE_THRESHOLD} B & storage ({len(large_symbols)} symbols):"
                 )
                 for i, (symbol, demangled, size, section) in enumerate(large_symbols):
                     lines.append(
@@ -500,7 +622,10 @@ class MemoryAnalyzerCLI(MemoryAnalyzer):
             # Sort by size descending
             sorted_ram_syms = sorted(ram_syms, key=lambda x: x[2], reverse=True)
             large_ram_syms = [
-                s for s in sorted_ram_syms if s[2] > self.RAM_SYMBOL_SIZE_THRESHOLD
+                s
+                for s in sorted_ram_syms
+                if s[2] > self.RAM_SYMBOL_SIZE_THRESHOLD
+                or s[1].endswith(_PSTORAGE_SUFFIX)
             ]
 
             lines.append(f"{name} ({mem.ram_total:,} B total RAM):")
@@ -518,13 +643,14 @@ class MemoryAnalyzerCLI(MemoryAnalyzer):
                 for symbol, demangled, size, section in large_ram_syms[:10]:
                     # Format section label consistently by stripping leading dot
                     section_label = section.lstrip(".") if section else ""
+                    display_name = _format_pstorage_name(demangled)
                     # Add ellipsis if name is truncated
-                    demangled_display = (
-                        f"{demangled[:70]}..." if len(demangled) > 70 else demangled
-                    )
-                    lines.append(
-                        f"    {size:>6,} B [{section_label}] {demangled_display}"
+                    display_name = (
+                        f"{display_name[:70]}..."
+                        if len(display_name) > 70
+                        else display_name
                     )
+                    lines.append(f"    {size:>6,} B [{section_label}] {display_name}")
                 if len(large_ram_syms) > 10:
                     lines.append(f"    ... and {len(large_ram_syms) - 10} more")
             lines.append("")
@@ -533,6 +659,11 @@ class MemoryAnalyzerCLI(MemoryAnalyzer):
         if self._cswtch_symbols:
             self._add_cswtch_analysis(lines)
 
+        # Function call frequency analysis
+        if self._function_call_counts:
+            self._add_function_call_analysis(lines)
+            self._add_inline_candidates(lines)
+
         lines.append(
             "Note: This analysis covers symbols in the ELF file. Some runtime allocations may not be included."
         )

esphome/analyze_memory/const.py

@@ -408,7 +408,6 @@ SYMBOL_PATTERNS = {
     ],
     "arduino_core": [
         "pinMode",
-        "resetPins",
         "millis",
         "micros",
         "delay(",  # More specific - Arduino delay function with parenthesis

esphome/automation.py

@@ -1,3 +1,4 @@
+from dataclasses import dataclass, field
 import logging
 
 import esphome.codegen as cg
@@ -137,6 +138,9 @@ UpdateComponentAction = cg.esphome_ns.class_("UpdateComponentAction", Action)
 SuspendComponentAction = cg.esphome_ns.class_("SuspendComponentAction", Action)
 ResumeComponentAction = cg.esphome_ns.class_("ResumeComponentAction", Action)
 Automation = cg.esphome_ns.class_("Automation")
+TriggerForwarder = cg.esphome_ns.class_("TriggerForwarder")
+TriggerOnTrueForwarder = cg.esphome_ns.class_("TriggerOnTrueForwarder")
+TriggerOnFalseForwarder = cg.esphome_ns.class_("TriggerOnFalseForwarder")
 
 LambdaCondition = cg.esphome_ns.class_("LambdaCondition", Condition)
 StatelessLambdaCondition = cg.esphome_ns.class_("StatelessLambdaCondition", Condition)
@@ -247,7 +251,9 @@ async def and_condition_to_code(
     args: TemplateArgsType,
 ) -> MockObj:
     conditions = await build_condition_list(config, template_arg, args)
-    return cg.new_Pvariable(condition_id, template_arg, conditions)
+    return cg.new_Pvariable(
+        condition_id, cg.TemplateArguments(len(conditions), *template_arg), conditions
+    )
 
 
 @register_condition("or", OrCondition, validate_condition_list)
@@ -258,7 +264,9 @@ async def or_condition_to_code(
     args: TemplateArgsType,
 ) -> MockObj:
     conditions = await build_condition_list(config, template_arg, args)
-    return cg.new_Pvariable(condition_id, template_arg, conditions)
+    return cg.new_Pvariable(
+        condition_id, cg.TemplateArguments(len(conditions), *template_arg), conditions
+    )
 
 
 @register_condition("all", AndCondition, validate_condition_list)
@@ -269,7 +277,9 @@ async def all_condition_to_code(
     args: TemplateArgsType,
 ) -> MockObj:
     conditions = await build_condition_list(config, template_arg, args)
-    return cg.new_Pvariable(condition_id, template_arg, conditions)
+    return cg.new_Pvariable(
+        condition_id, cg.TemplateArguments(len(conditions), *template_arg), conditions
+    )
 
 
 @register_condition("any", OrCondition, validate_condition_list)
@@ -280,7 +290,9 @@ async def any_condition_to_code(
     args: TemplateArgsType,
 ) -> MockObj:
     conditions = await build_condition_list(config, template_arg, args)
-    return cg.new_Pvariable(condition_id, template_arg, conditions)
+    return cg.new_Pvariable(
+        condition_id, cg.TemplateArguments(len(conditions), *template_arg), conditions
+    )
 
 
 @register_condition("not", NotCondition, validate_potentially_and_condition)
@@ -302,7 +314,9 @@ async def xor_condition_to_code(
     args: TemplateArgsType,
 ) -> MockObj:
     conditions = await build_condition_list(config, template_arg, args)
-    return cg.new_Pvariable(condition_id, template_arg, conditions)
+    return cg.new_Pvariable(
+        condition_id, cg.TemplateArguments(len(conditions), *template_arg), conditions
+    )
 
 
 @register_condition("lambda", LambdaCondition, cv.returning_lambda)
@@ -413,13 +427,16 @@ async def if_action_to_code(
     template_arg: cg.TemplateArguments,
     args: TemplateArgsType,
 ) -> MockObj:
+    has_else = CONF_ELSE in config
+    # Prepend HasElse bool to template arguments: IfAction<HasElse, Ts...>
+    if_template_arg = cg.TemplateArguments(has_else, *template_arg)
     cond_conf = next(el for el in config if el in (CONF_ANY, CONF_ALL, CONF_CONDITION))
     condition = await build_condition(config[cond_conf], template_arg, args)
-    var = cg.new_Pvariable(action_id, template_arg, condition)
+    var = cg.new_Pvariable(action_id, if_template_arg, condition)
     if CONF_THEN in config:
         actions = await build_action_list(config[CONF_THEN], template_arg, args)
         cg.add(var.add_then(actions))
-    if CONF_ELSE in config:
+    if has_else:
         actions = await build_action_list(config[CONF_ELSE], template_arg, args)
         cg.add(var.add_else(actions))
     return var
@@ -658,3 +675,76 @@ async def build_automation(
     actions = await build_action_list(config[CONF_THEN], templ, args)
     cg.add(obj.add_actions(actions))
     return obj
+
+
+async def build_callback_automation(
+    parent: MockObj,
+    callback_method: str,
+    args: TemplateArgsType,
+    config: ConfigType,
+    forwarder: MockObj | MockObjClass | None = None,
+) -> None:
+    """Build an Automation and register it as a callback on the parent.
+
+    Eliminates the need for a Trigger wrapper object by registering the
+    automation's trigger() directly as a callback on the parent component.
+
+    Uses template forwarder structs so the compiler deduplicates the operator()
+    body across all call sites with the same signature. The forwarder must be
+    pointer-sized (single Automation* field) to fit inline in Callback::ctx_
+    and avoid heap allocation.
+
+    :param parent: The component object (e.g., button, sensor).
+    :param callback_method: Name of the callback method (e.g., "add_on_press_callback").
+    :param args: Automation template args as list of (type, name) tuples.
+    :param config: The automation config dict.
+    :param forwarder: Optional forwarder type to use instead of the default
+        TriggerForwarder<Ts...>. Pass any struct type whose aggregate init takes
+        a single Automation pointer (e.g., TriggerOnTrueForwarder).
+    """
+    arg_types = [arg[0] for arg in args]
+    templ = cg.TemplateArguments(*arg_types)
+    obj = cg.new_Pvariable(config[CONF_AUTOMATION_ID], templ)
+    actions = await build_action_list(config[CONF_THEN], templ, args)
+    cg.add(obj.add_actions(actions))
+    # Use template forwarder structs for deduplication. The compiler generates
+    # one operator() per forwarder type; different automation pointers are just
+    # data in the struct.
+    if forwarder is None:
+        forwarder = TriggerForwarder.template(templ)
+    # RawExpression for aggregate init — both forwarder and obj are codegen
+    # MockObjs (not user input), and there's no Expression type for positional
+    # aggregate initialization (StructInitializer uses named fields).
+    cg.add(getattr(parent, callback_method)(cg.RawExpression(f"{forwarder}{{{obj}}}")))
+
+
+@dataclass(frozen=True, slots=True)
+class CallbackAutomation:
+    """A single callback automation entry for build_callback_automations."""
+
+    conf_key: str
+    callback_method: str
+    args: TemplateArgsType = field(default_factory=list)
+    forwarder: MockObj | MockObjClass | None = None
+
+
+async def build_callback_automations(
+    parent: MockObj,
+    config: ConfigType,
+    entries: tuple[CallbackAutomation, ...],
+) -> None:
+    """Build multiple callback automations from a tuple of entries.
+
+    :param parent: The component object (e.g., button, sensor).
+    :param config: The full component config dict.
+    :param entries: Tuple of CallbackAutomation entries to process.
+    """
+    for entry in entries:
+        for conf in config.get(entry.conf_key, []):
+            await build_callback_automation(
+                parent,
+                entry.callback_method,
+                entry.args,
+                conf,
+                forwarder=entry.forwarder,
+            )

esphome/build_gen/espidf.py

@@ -53,6 +53,13 @@ def get_project_cmakelists() -> str:
     variant = get_esp32_variant()
     idf_target = variant.lower().replace("-", "")
 
+    # Extract compile definitions from build flags (-DXXX -> XXX)
+    compile_defs = [flag for flag in CORE.build_flags if flag.startswith("-D")]
+    extra_compile_options = "\n".join(
+        f'idf_build_set_property(COMPILE_OPTIONS "{compile_def}" APPEND)'
+        for compile_def in compile_defs
+    )
+
     return f"""\
 # Auto-generated by ESPHome
 cmake_minimum_required(VERSION 3.16)
@@ -61,6 +68,9 @@ set(IDF_TARGET {idf_target})
 set(EXTRA_COMPONENT_DIRS ${{CMAKE_SOURCE_DIR}}/src)
 
 include($ENV{{IDF_PATH}}/tools/cmake/project.cmake)
+
+{extra_compile_options}
+
 project({CORE.name})
 """
 
@@ -70,10 +80,6 @@ def get_component_cmakelists(minimal: bool = False) -> str:
     idf_requires = [] if minimal else (get_available_components() or [])
     requires_str = " ".join(idf_requires)
 
-    # Extract compile definitions from build flags (-DXXX -> XXX)
-    compile_defs = [flag[2:] for flag in CORE.build_flags if flag.startswith("-D")]
-    compile_defs_str = "\n    ".join(sorted(compile_defs)) if compile_defs else ""
-
     # Extract compile options (-W flags, excluding linker flags)
     compile_opts = [
         flag
@@ -104,11 +110,6 @@ idf_component_register(
 # Apply C++ standard
 target_compile_features(${{COMPONENT_LIB}} PUBLIC cxx_std_20)
 
-# ESPHome compile definitions
-target_compile_definitions(${{COMPONENT_LIB}} PUBLIC
-    {compile_defs_str}
-)
-
 # ESPHome compile options
 target_compile_options(${{COMPONENT_LIB}} PUBLIC
     {compile_opts_str}

esphome/codegen.py

@@ -79,6 +79,7 @@ from esphome.cpp_types import (  # noqa: F401
     float_,
     global_ns,
     gpio_Flags,
+    int8,
     int16,
     int32,
     int64,

esphome/components/absolute_humidity/absolute_humidity.cpp

@@ -1,22 +1,29 @@
 #include "esphome/core/log.h"
 #include "absolute_humidity.h"
 
-namespace esphome {
-namespace absolute_humidity {
+namespace esphome::absolute_humidity {
 
-static const char *const TAG = "absolute_humidity.sensor";
+static const char *const TAG{"absolute_humidity.sensor"};
 
 void AbsoluteHumidityComponent::setup() {
+  this->temperature_sensor_->add_on_state_callback([this](float state) {
+    this->temperature_ = state;
+    this->enable_loop();
+  });
   ESP_LOGD(TAG, "  Added callback for temperature '%s'", this->temperature_sensor_->get_name().c_str());
-  this->temperature_sensor_->add_on_state_callback([this](float state) { this->temperature_callback_(state); });
+  // Get initial value
   if (this->temperature_sensor_->has_state()) {
-    this->temperature_callback_(this->temperature_sensor_->get_state());
+    this->temperature_ = this->temperature_sensor_->get_state();
   }
 
+  this->humidity_sensor_->add_on_state_callback([this](float state) {
+    this->humidity_ = state;
+    this->enable_loop();
+  });
   ESP_LOGD(TAG, "  Added callback for relative humidity '%s'", this->humidity_sensor_->get_name().c_str());
-  this->humidity_sensor_->add_on_state_callback([this](float state) { this->humidity_callback_(state); });
+  // Get initial value
   if (this->humidity_sensor_->has_state()) {
-    this->humidity_callback_(this->humidity_sensor_->get_state());
+    this->humidity_ = this->humidity_sensor_->get_state();
   }
 }
 
@@ -46,14 +53,12 @@ void AbsoluteHumidityComponent::dump_config() {
 }
 
 void AbsoluteHumidityComponent::loop() {
-  if (!this->next_update_) {
-    return;
-  }
-  this->next_update_ = false;
+  // Only run once
+  this->disable_loop();
 
   // Ensure we have source data
-  const bool no_temperature = std::isnan(this->temperature_);
-  const bool no_humidity = std::isnan(this->humidity_);
+  const bool no_temperature{std::isnan(this->temperature_)};
+  const bool no_humidity{std::isnan(this->humidity_)};
   if (no_temperature || no_humidity) {
     if (no_temperature) {
       ESP_LOGW(TAG, "No valid state from temperature sensor!");
@@ -67,9 +72,9 @@ void AbsoluteHumidityComponent::loop() {
   }
 
   // Convert to desired units
-  const float temperature_c = this->temperature_;
-  const float temperature_k = temperature_c + 273.15;
-  const float hr = this->humidity_ / 100;
+  const float temperature_c{this->temperature_};
+  const float temperature_k{temperature_c + 273.15f};
+  const float hr{this->humidity_ / 100.0f};
 
   // Calculate saturation vapor pressure
   float es;
@@ -90,7 +95,7 @@ void AbsoluteHumidityComponent::loop() {
   }
 
   // Calculate absolute humidity
-  const float absolute_humidity = vapor_density(es, hr, temperature_k);
+  const float absolute_humidity{vapor_density(es, hr, temperature_k)};
 
   ESP_LOGD(TAG, "Saturation vapor pressure %f kPa, absolute humidity %f g/m³", es, absolute_humidity);
 
@@ -103,16 +108,16 @@ void AbsoluteHumidityComponent::loop() {
 // More accurate than Tetens in normal meteorologic conditions
 float AbsoluteHumidityComponent::es_buck(float temperature_c) {
   float a, b, c, d;
-  if (temperature_c >= 0) {
-    a = 0.61121;
-    b = 18.678;
-    c = 234.5;
-    d = 257.14;
+  if (temperature_c >= 0.0f) {
+    a = 0.61121f;
+    b = 18.678f;
+    c = 234.5f;
+    d = 257.14f;
   } else {
-    a = 0.61115;
-    b = 18.678;
-    c = 233.7;
-    d = 279.82;
+    a = 0.61115f;
+    b = 18.678f;
+    c = 233.7f;
+    d = 279.82f;
   }
   return a * expf((b - (temperature_c / c)) * (temperature_c / (d + temperature_c)));
 }
@@ -120,14 +125,14 @@ float AbsoluteHumidityComponent::es_buck(float temperature_c) {
 // Tetens equation (https://en.wikipedia.org/wiki/Tetens_equation)
 float AbsoluteHumidityComponent::es_tetens(float temperature_c) {
   float a, b;
-  if (temperature_c >= 0) {
-    a = 17.27;
-    b = 237.3;
+  if (temperature_c >= 0.0f) {
+    a = 17.27f;
+    b = 237.3f;
   } else {
-    a = 21.875;
-    b = 265.5;
+    a = 21.875f;
+    b = 265.5f;
   }
-  return 0.61078 * expf((a * temperature_c) / (temperature_c + b));
+  return 0.61078f * expf((a * temperature_c) / (temperature_c + b));
 }
 
 // Wobus equation
@@ -146,18 +151,18 @@ float AbsoluteHumidityComponent::es_wobus(float t) {
   //
   //     Baker, Schlatter  17-MAY-1982     Original version.
 
-  const float c0 = +0.99999683e00;
-  const float c1 = -0.90826951e-02;
-  const float c2 = +0.78736169e-04;
-  const float c3 = -0.61117958e-06;
-  const float c4 = +0.43884187e-08;
-  const float c5 = -0.29883885e-10;
-  const float c6 = +0.21874425e-12;
-  const float c7 = -0.17892321e-14;
-  const float c8 = +0.11112018e-16;
-  const float c9 = -0.30994571e-19;
-  const float p = c0 + t * (c1 + t * (c2 + t * (c3 + t * (c4 + t * (c5 + t * (c6 + t * (c7 + t * (c8 + t * (c9)))))))));
-  return 0.61078 / pow(p, 8);
+  constexpr float c0{+0.99999683e+00f};
+  constexpr float c1{-0.90826951e-02f};
+  constexpr float c2{+0.78736169e-04f};
+  constexpr float c3{-0.61117958e-06f};
+  constexpr float c4{+0.43884187e-08f};
+  constexpr float c5{-0.29883885e-10f};
+  constexpr float c6{+0.21874425e-12f};
+  constexpr float c7{-0.17892321e-14f};
+  constexpr float c8{+0.11112018e-16f};
+  constexpr float c9{-0.30994571e-19f};
+  const float p{c0 + t * (c1 + t * (c2 + t * (c3 + t * (c4 + t * (c5 + t * (c6 + t * (c7 + t * (c8 + t * (c9)))))))))};
+  return 0.61078f / powf(p, 8.0f);
 }
 
 // From https://www.environmentalbiophysics.org/chalk-talk-how-to-calculate-absolute-humidity/
@@ -168,11 +173,10 @@ float AbsoluteHumidityComponent::vapor_density(float es, float hr, float ta) {
   // hr = relative humidity [0-1]
   // ta = absolute temperature (K)
 
-  const float ea = hr * es * 1000;   // vapor pressure of the air (Pa)
-  const float mw = 18.01528;         // molar mass of water (g⋅mol⁻¹)
-  const float r = 8.31446261815324;  // molar gas constant (J⋅K⁻¹)
+  const float ea{hr * es * 1000.0f};  // vapor pressure of the air (Pa)
+  const float mw{18.01528f};          // molar mass of water (g⋅mol⁻¹)
+  const float r{8.31446261815324f};   // molar gas constant (J⋅K⁻¹)
   return (ea * mw) / (r * ta);
 }
 
-}  // namespace absolute_humidity
-}  // namespace esphome
+}  // namespace esphome::absolute_humidity

esphome/components/absolute_humidity/absolute_humidity.h

@@ -3,8 +3,7 @@
 #include "esphome/core/component.h"
 #include "esphome/components/sensor/sensor.h"
 
-namespace esphome {
-namespace absolute_humidity {
+namespace esphome::absolute_humidity {
 
 /// Enum listing all implemented saturation vapor pressure equations.
 enum SaturationVaporPressureEquation {
@@ -16,8 +15,6 @@ enum SaturationVaporPressureEquation {
 /// This class implements calculation of absolute humidity from temperature and relative humidity.
 class AbsoluteHumidityComponent : public sensor::Sensor, public Component {
  public:
-  AbsoluteHumidityComponent() = default;
-
   void set_temperature_sensor(sensor::Sensor *temperature_sensor) { this->temperature_sensor_ = temperature_sensor; }
   void set_humidity_sensor(sensor::Sensor *humidity_sensor) { this->humidity_sensor_ = humidity_sensor; }
   void set_equation(SaturationVaporPressureEquation equation) { this->equation_ = equation; }
@@ -27,15 +24,6 @@ class AbsoluteHumidityComponent : public sensor::Sensor, public Component {
   void loop() override;
 
  protected:
-  void temperature_callback_(float state) {
-    this->next_update_ = true;
-    this->temperature_ = state;
-  }
-  void humidity_callback_(float state) {
-    this->next_update_ = true;
-    this->humidity_ = state;
-  }
-
   /** Buck equation for saturation vapor pressure in kPa.
    *
    * @param temperature_c Air temperature in °C.
@@ -57,19 +45,15 @@ class AbsoluteHumidityComponent : public sensor::Sensor, public Component {
    * @param es Saturation vapor pressure in kPa.
    * @param hr Relative humidity 0 to 1.
    * @param ta Absolute temperature in K.
-   * @param heater_duration The duration in ms that the heater should turn on for when measuring.
    */
   static float vapor_density(float es, float hr, float ta);
 
   sensor::Sensor *temperature_sensor_{nullptr};
   sensor::Sensor *humidity_sensor_{nullptr};
 
-  bool next_update_{false};
-
   float temperature_{NAN};
   float humidity_{NAN};
   SaturationVaporPressureEquation equation_;
 };
 
-}  // namespace absolute_humidity
-}  // namespace esphome
+}  // namespace esphome::absolute_humidity

esphome/components/adc/adc_sensor.h

@@ -22,7 +22,8 @@ namespace adc {
 
 #ifdef USE_ESP32
 // clang-format off
-#if (ESP_IDF_VERSION_MAJOR == 5 && \
+#if ESP_IDF_VERSION_MAJOR >= 6 || \
+    (ESP_IDF_VERSION_MAJOR == 5 && \
      ((ESP_IDF_VERSION_MINOR == 0 && ESP_IDF_VERSION_PATCH >= 5) || \
       (ESP_IDF_VERSION_MINOR == 1 && ESP_IDF_VERSION_PATCH >= 3) || \
       (ESP_IDF_VERSION_MINOR >= 2)) \

esphome/components/adc/adc_sensor_esp32.cpp

@@ -2,6 +2,7 @@
 
 #include "adc_sensor.h"
 #include "esphome/core/log.h"
+#include <cinttypes>
 
 namespace esphome {
 namespace adc {
@@ -346,7 +347,8 @@ float ADCSensor::sample_autorange_() {
   ESP_LOGVV(TAG, "Autorange summary:");
   ESP_LOGVV(TAG, "  Raw readings: 12db=%d, 6db=%d, 2.5db=%d, 0db=%d", raw12, raw6, raw2, raw0);
   ESP_LOGVV(TAG, "  Voltages: 12db=%.6f, 6db=%.6f, 2.5db=%.6f, 0db=%.6f", mv12, mv6, mv2, mv0);
-  ESP_LOGVV(TAG, "  Coefficients: c12=%u, c6=%u, c2=%u, c0=%u, sum=%u", c12, c6, c2, c0, csum);
+  ESP_LOGVV(TAG, "  Coefficients: c12=%" PRIu32 ", c6=%" PRIu32 ", c2=%" PRIu32 ", c0=%" PRIu32 ", sum=%" PRIu32, c12,
+            c6, c2, c0, csum);
 
   if (csum == 0) {
     ESP_LOGE(TAG, "Invalid weight sum in autorange calculation");
@@ -354,8 +356,10 @@ float ADCSensor::sample_autorange_() {
   }
 
   const float final_result = (mv12 * c12 + mv6 * c6 + mv2 * c2 + mv0 * c0) / csum;
-  ESP_LOGV(TAG, "Autorange final: (%.6f*%u + %.6f*%u + %.6f*%u + %.6f*%u)/%u = %.6fV", mv12, c12, mv6, c6, mv2, c2, mv0,
-           c0, csum, final_result);
+  ESP_LOGV(TAG,
+           "Autorange final: (%.6f*%" PRIu32 " + %.6f*%" PRIu32 " + %.6f*%" PRIu32 " + %.6f*%" PRIu32 ")/%" PRIu32
+           " = %.6fV",
+           mv12, c12, mv6, c6, mv2, c2, mv0, c0, csum, final_result);
 
   return final_result;
 }

esphome/components/ads1118/__init__.py

@@ -12,11 +12,15 @@ CONF_ADS1118_ID = "ads1118_id"
 ads1118_ns = cg.esphome_ns.namespace("ads1118")
 ADS1118 = ads1118_ns.class_("ADS1118", cg.Component, spi.SPIDevice)
 
-CONFIG_SCHEMA = cv.Schema(
-    {
-        cv.GenerateID(): cv.declare_id(ADS1118),
-    }
-).extend(spi.spi_device_schema(cs_pin_required=True))
+CONFIG_SCHEMA = (
+    cv.Schema(
+        {
+            cv.GenerateID(): cv.declare_id(ADS1118),
+        }
+    )
+    .extend(spi.spi_device_schema(cs_pin_required=True))
+    .extend(cv.COMPONENT_SCHEMA)
+)
 
 
 async def to_code(config):

esphome/components/ags10/sensor.py

@@ -35,7 +35,7 @@ CONFIG_SCHEMA = (
     cv.Schema(
         {
             cv.GenerateID(): cv.declare_id(AGS10Component),
-            cv.Optional(CONF_TVOC): sensor.sensor_schema(
+            cv.Required(CONF_TVOC): sensor.sensor_schema(
                 unit_of_measurement=UNIT_PARTS_PER_BILLION,
                 icon=ICON_RADIATOR,
                 accuracy_decimals=0,
@@ -97,7 +97,7 @@ AGS10_NEW_I2C_ADDRESS_SCHEMA = cv.maybe_simple_value(
 async def ags10newi2caddress_to_code(config, action_id, template_arg, args):
     var = cg.new_Pvariable(action_id, template_arg)
     await cg.register_parented(var, config[CONF_ID])
-    address = await cg.templatable(config[CONF_ADDRESS], args, int)
+    address = await cg.templatable(config[CONF_ADDRESS], args, cg.uint8)
     cg.add(var.set_new_address(address))
     return var
 
@@ -112,7 +112,9 @@ AGS10_SET_ZERO_POINT_ACTION_MODE = {
 AGS10_SET_ZERO_POINT_SCHEMA = cv.Schema(
     {
         cv.GenerateID(): cv.use_id(AGS10Component),
-        cv.Required(CONF_MODE): cv.enum(AGS10_SET_ZERO_POINT_ACTION_MODE, upper=True),
+        cv.Required(CONF_MODE): cv.templatable(
+            cv.enum(AGS10_SET_ZERO_POINT_ACTION_MODE, upper=True)
+        ),
         cv.Optional(CONF_VALUE, default=0xFFFF): cv.templatable(cv.uint16_t),
     },
 )
@@ -127,8 +129,10 @@ AGS10_SET_ZERO_POINT_SCHEMA = cv.Schema(
 async def ags10setzeropoint_to_code(config, action_id, template_arg, args):
     var = cg.new_Pvariable(action_id, template_arg)
     await cg.register_parented(var, config[CONF_ID])
-    mode = await cg.templatable(config.get(CONF_MODE), args, enumerate)
+    mode = await cg.templatable(
+        config.get(CONF_MODE), args, AGS10SetZeroPointActionMode
+    )
     cg.add(var.set_mode(mode))
-    value = await cg.templatable(config[CONF_VALUE], args, int)
+    value = await cg.templatable(config[CONF_VALUE], args, cg.uint16)
     cg.add(var.set_value(value))
     return var

esphome/components/aic3204/audio_dac.py

@@ -43,7 +43,7 @@ async def aic3204_set_volume_to_code(config, action_id, template_arg, args):
     paren = await cg.get_variable(config[CONF_ID])
     var = cg.new_Pvariable(action_id, template_arg, paren)
 
-    template_ = await cg.templatable(config.get(CONF_MODE), args, int)
+    template_ = await cg.templatable(config.get(CONF_MODE), args, cg.uint8)
     cg.add(var.set_auto_mute_mode(template_))
 
     return var

esphome/components/alarm_control_panel/__init__.py

@@ -10,7 +10,6 @@ from esphome.const import (
     CONF_ID,
     CONF_MQTT_ID,
     CONF_ON_STATE,
-    CONF_TRIGGER_ID,
     CONF_WEB_SERVER,
 )
 from esphome.core import CORE, CoroPriority, coroutine_with_priority
@@ -34,39 +33,9 @@ CONF_ON_READY = "on_ready"
 alarm_control_panel_ns = cg.esphome_ns.namespace("alarm_control_panel")
 AlarmControlPanel = alarm_control_panel_ns.class_("AlarmControlPanel", cg.EntityBase)
 
-StateTrigger = alarm_control_panel_ns.class_(
-    "StateTrigger", automation.Trigger.template()
-)
-TriggeredTrigger = alarm_control_panel_ns.class_(
-    "TriggeredTrigger", automation.Trigger.template()
-)
-ClearedTrigger = alarm_control_panel_ns.class_(
-    "ClearedTrigger", automation.Trigger.template()
-)
-ArmingTrigger = alarm_control_panel_ns.class_(
-    "ArmingTrigger", automation.Trigger.template()
-)
-PendingTrigger = alarm_control_panel_ns.class_(
-    "PendingTrigger", automation.Trigger.template()
-)
-ArmedHomeTrigger = alarm_control_panel_ns.class_(
-    "ArmedHomeTrigger", automation.Trigger.template()
-)
-ArmedNightTrigger = alarm_control_panel_ns.class_(
-    "ArmedNightTrigger", automation.Trigger.template()
-)
-ArmedAwayTrigger = alarm_control_panel_ns.class_(
-    "ArmedAwayTrigger", automation.Trigger.template()
-)
-DisarmedTrigger = alarm_control_panel_ns.class_(
-    "DisarmedTrigger", automation.Trigger.template()
-)
-ChimeTrigger = alarm_control_panel_ns.class_(
-    "ChimeTrigger", automation.Trigger.template()
-)
-ReadyTrigger = alarm_control_panel_ns.class_(
-    "ReadyTrigger", automation.Trigger.template()
-)
+StateAnyForwarder = alarm_control_panel_ns.class_("StateAnyForwarder")
+StateEnterForwarder = alarm_control_panel_ns.class_("StateEnterForwarder")
+AlarmControlPanelState = alarm_control_panel_ns.enum("AlarmControlPanelState")
 
 ArmAwayAction = alarm_control_panel_ns.class_("ArmAwayAction", automation.Action)
 ArmHomeAction = alarm_control_panel_ns.class_("ArmHomeAction", automation.Action)
@@ -89,61 +58,17 @@ _ALARM_CONTROL_PANEL_SCHEMA = (
             cv.OnlyWith(CONF_MQTT_ID, "mqtt"): cv.declare_id(
                 mqtt.MQTTAlarmControlPanelComponent
             ),
-            cv.Optional(CONF_ON_STATE): automation.validate_automation(
-                {
-                    cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(StateTrigger),
-                }
-            ),
-            cv.Optional(CONF_ON_TRIGGERED): automation.validate_automation(
-                {
-                    cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(TriggeredTrigger),
-                }
-            ),
-            cv.Optional(CONF_ON_ARMING): automation.validate_automation(
-                {
-                    cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(ArmingTrigger),
-                }
-            ),
-            cv.Optional(CONF_ON_PENDING): automation.validate_automation(
-                {
-                    cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(PendingTrigger),
-                }
-            ),
-            cv.Optional(CONF_ON_ARMED_HOME): automation.validate_automation(
-                {
-                    cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(ArmedHomeTrigger),
-                }
-            ),
-            cv.Optional(CONF_ON_ARMED_NIGHT): automation.validate_automation(
-                {
-                    cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(ArmedNightTrigger),
-                }
-            ),
-            cv.Optional(CONF_ON_ARMED_AWAY): automation.validate_automation(
-                {
-                    cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(ArmedAwayTrigger),
-                }
-            ),
-            cv.Optional(CONF_ON_DISARMED): automation.validate_automation(
-                {
-                    cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(DisarmedTrigger),
-                }
-            ),
-            cv.Optional(CONF_ON_CLEARED): automation.validate_automation(
-                {
-                    cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(ClearedTrigger),
-                }
-            ),
-            cv.Optional(CONF_ON_CHIME): automation.validate_automation(
-                {
-                    cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(ChimeTrigger),
-                }
-            ),
-            cv.Optional(CONF_ON_READY): automation.validate_automation(
-                {
-                    cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(ReadyTrigger),
-                }
-            ),
+            cv.Optional(CONF_ON_STATE): automation.validate_automation({}),
+            cv.Optional(CONF_ON_TRIGGERED): automation.validate_automation({}),
+            cv.Optional(CONF_ON_ARMING): automation.validate_automation({}),
+            cv.Optional(CONF_ON_PENDING): automation.validate_automation({}),
+            cv.Optional(CONF_ON_ARMED_HOME): automation.validate_automation({}),
+            cv.Optional(CONF_ON_ARMED_NIGHT): automation.validate_automation({}),
+            cv.Optional(CONF_ON_ARMED_AWAY): automation.validate_automation({}),
+            cv.Optional(CONF_ON_DISARMED): automation.validate_automation({}),
+            cv.Optional(CONF_ON_CLEARED): automation.validate_automation({}),
+            cv.Optional(CONF_ON_CHIME): automation.validate_automation({}),
+            cv.Optional(CONF_ON_READY): automation.validate_automation({}),
         }
     )
 )
@@ -186,41 +111,66 @@ ALARM_CONTROL_PANEL_CONDITION_SCHEMA = maybe_simple_id(
 )
 
 
+_CALLBACK_AUTOMATIONS = (
+    automation.CallbackAutomation(
+        CONF_ON_STATE, "add_on_state_callback", forwarder=StateAnyForwarder
+    ),
+    automation.CallbackAutomation(
+        CONF_ON_TRIGGERED,
+        "add_on_state_callback",
+        forwarder=StateEnterForwarder.template(
+            AlarmControlPanelState.ACP_STATE_TRIGGERED
+        ),
+    ),
+    automation.CallbackAutomation(
+        CONF_ON_ARMING,
+        "add_on_state_callback",
+        forwarder=StateEnterForwarder.template(AlarmControlPanelState.ACP_STATE_ARMING),
+    ),
+    automation.CallbackAutomation(
+        CONF_ON_PENDING,
+        "add_on_state_callback",
+        forwarder=StateEnterForwarder.template(
+            AlarmControlPanelState.ACP_STATE_PENDING
+        ),
+    ),
+    automation.CallbackAutomation(
+        CONF_ON_ARMED_HOME,
+        "add_on_state_callback",
+        forwarder=StateEnterForwarder.template(
+            AlarmControlPanelState.ACP_STATE_ARMED_HOME
+        ),
+    ),
+    automation.CallbackAutomation(
+        CONF_ON_ARMED_NIGHT,
+        "add_on_state_callback",
+        forwarder=StateEnterForwarder.template(
+            AlarmControlPanelState.ACP_STATE_ARMED_NIGHT
+        ),
+    ),
+    automation.CallbackAutomation(
+        CONF_ON_ARMED_AWAY,
+        "add_on_state_callback",
+        forwarder=StateEnterForwarder.template(
+            AlarmControlPanelState.ACP_STATE_ARMED_AWAY
+        ),
+    ),
+    automation.CallbackAutomation(
+        CONF_ON_DISARMED,
+        "add_on_state_callback",
+        forwarder=StateEnterForwarder.template(
+            AlarmControlPanelState.ACP_STATE_DISARMED
+        ),
+    ),
+    automation.CallbackAutomation(CONF_ON_CLEARED, "add_on_cleared_callback"),
+    automation.CallbackAutomation(CONF_ON_CHIME, "add_on_chime_callback"),
+    automation.CallbackAutomation(CONF_ON_READY, "add_on_ready_callback"),
+)
+
+
 @setup_entity("alarm_control_panel")
 async def setup_alarm_control_panel_core_(var, config):
-    for conf in config.get(CONF_ON_STATE, []):
-        trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
-        await automation.build_automation(trigger, [], conf)
-    for conf in config.get(CONF_ON_TRIGGERED, []):
-        trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
-        await automation.build_automation(trigger, [], conf)
-    for conf in config.get(CONF_ON_ARMING, []):
-        trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
-        await automation.build_automation(trigger, [], conf)
-    for conf in config.get(CONF_ON_PENDING, []):
-        trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
-        await automation.build_automation(trigger, [], conf)
-    for conf in config.get(CONF_ON_ARMED_HOME, []):
-        trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
-        await automation.build_automation(trigger, [], conf)
-    for conf in config.get(CONF_ON_ARMED_NIGHT, []):
-        trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
-        await automation.build_automation(trigger, [], conf)
-    for conf in config.get(CONF_ON_ARMED_AWAY, []):
-        trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
-        await automation.build_automation(trigger, [], conf)
-    for conf in config.get(CONF_ON_DISARMED, []):
-        trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
-        await automation.build_automation(trigger, [], conf)
-    for conf in config.get(CONF_ON_CLEARED, []):
-        trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
-        await automation.build_automation(trigger, [], conf)
-    for conf in config.get(CONF_ON_CHIME, []):
-        trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
-        await automation.build_automation(trigger, [], conf)
-    for conf in config.get(CONF_ON_READY, []):
-        trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
-        await automation.build_automation(trigger, [], conf)
+    await automation.build_callback_automations(var, config, _CALLBACK_AUTOMATIONS)
     if web_server_config := config.get(CONF_WEB_SERVER):
         await web_server.add_entity_config(var, web_server_config)
     if mqtt_id := config.get(CONF_MQTT_ID):

esphome/components/alarm_control_panel/alarm_control_panel.cpp

@@ -31,12 +31,12 @@ void AlarmControlPanel::publish_state(AlarmControlPanelState state) {
   this->last_update_ = millis();
   if (state != this->current_state_) {
     auto prev_state = this->current_state_;
-    ESP_LOGD(TAG, "'%s' >> %s (was %s)", this->get_name().c_str(),
+    ESP_LOGV(TAG, "'%s' >> %s (was %s)", this->get_name().c_str(),
              LOG_STR_ARG(alarm_control_panel_state_to_string(state)),
              LOG_STR_ARG(alarm_control_panel_state_to_string(prev_state)));
     this->current_state_ = state;
-    // Single state callback - triggers check get_state() for specific states
-    this->state_callback_.call();
+    // Single state callback - listeners receive the new state as an argument
+    this->state_callback_.call(state);
 #if defined(USE_ALARM_CONTROL_PANEL) && defined(USE_CONTROLLER_REGISTRY)
     ControllerRegistry::notify_alarm_control_panel_update(this);
 #endif
@@ -51,22 +51,6 @@ void AlarmControlPanel::publish_state(AlarmControlPanelState state) {
   }
 }
 
-void AlarmControlPanel::add_on_state_callback(std::function<void()> &&callback) {
-  this->state_callback_.add(std::move(callback));
-}
-
-void AlarmControlPanel::add_on_cleared_callback(std::function<void()> &&callback) {
-  this->cleared_callback_.add(std::move(callback));
-}
-
-void AlarmControlPanel::add_on_chime_callback(std::function<void()> &&callback) {
-  this->chime_callback_.add(std::move(callback));
-}
-
-void AlarmControlPanel::add_on_ready_callback(std::function<void()> &&callback) {
-  this->ready_callback_.add(std::move(callback));
-}
-
 void AlarmControlPanel::arm_with_code_(AlarmControlPanelCall &(AlarmControlPanelCall::*arm_method)(),
                                        const char *code) {
   auto call = this->make_call();

esphome/components/alarm_control_panel/alarm_control_panel.h

@@ -37,25 +37,24 @@ class AlarmControlPanel : public EntityBase {
    *
    * @param callback The callback function
    */
-  void add_on_state_callback(std::function<void()> &&callback);
+  template<typename F> void add_on_state_callback(F &&callback) {
+    this->state_callback_.add(std::forward<F>(callback));
+  }
 
-  /** Add a callback for when the state of the alarm_control_panel clears from triggered
-   *
-   * @param callback The callback function
-   */
-  void add_on_cleared_callback(std::function<void()> &&callback);
+  /** Add a callback for when the state of the alarm_control_panel clears from triggered. */
+  template<typename F> void add_on_cleared_callback(F &&callback) {
+    this->cleared_callback_.add(std::forward<F>(callback));
+  }
 
-  /** Add a callback for when a chime zone goes from closed to open
-   *
-   * @param callback The callback function
-   */
-  void add_on_chime_callback(std::function<void()> &&callback);
+  /** Add a callback for when a chime zone goes from closed to open. */
+  template<typename F> void add_on_chime_callback(F &&callback) {
+    this->chime_callback_.add(std::forward<F>(callback));
+  }
 
-  /** Add a callback for when a ready state changes
-   *
-   * @param callback The callback function
-   */
-  void add_on_ready_callback(std::function<void()> &&callback);
+  /** Add a callback for when a ready state changes. */
+  template<typename F> void add_on_ready_callback(F &&callback) {
+    this->ready_callback_.add(std::forward<F>(callback));
+  }
 
   /** A numeric representation of the supported features as per HomeAssistant
    *
@@ -146,8 +145,8 @@ class AlarmControlPanel : public EntityBase {
   uint32_t last_update_;
   // the call control function
   virtual void control(const AlarmControlPanelCall &call) = 0;
-  // state callback - triggers check get_state() for specific state
-  LazyCallbackManager<void()> state_callback_{};
+  // state callback - passes the new state to listeners
+  LazyCallbackManager<void(AlarmControlPanelState)> state_callback_{};
   // clear callback - fires when leaving TRIGGERED state
   LazyCallbackManager<void()> cleared_callback_{};
   // chime callback

esphome/components/alarm_control_panel/automation.h

@@ -5,60 +5,27 @@
 
 namespace esphome::alarm_control_panel {
 
-/// Trigger on any state change
-class StateTrigger : public Trigger<> {
- public:
-  explicit StateTrigger(AlarmControlPanel *alarm_control_panel) {
-    alarm_control_panel->add_on_state_callback([this]() { this->trigger(); });
+/// Callback forwarder that triggers an Automation<> on any state change.
+/// Pointer-sized (single Automation* field) to fit inline in Callback::ctx_.
+struct StateAnyForwarder {
+  Automation<> *automation;
+  void operator()(AlarmControlPanelState /*state*/) const { this->automation->trigger(); }
+};
+
+/// Callback forwarder that triggers an Automation<> only when the alarm enters a specific state.
+/// Pointer-sized (single Automation* field) to fit inline in Callback::ctx_.
+template<AlarmControlPanelState State> struct StateEnterForwarder {
+  Automation<> *automation;
+  void operator()(AlarmControlPanelState state) const {
+    if (state == State)
+      this->automation->trigger();
   }
 };
 
-/// Template trigger that fires when entering a specific state
-template<AlarmControlPanelState State> class StateEnterTrigger : public Trigger<> {
- public:
-  explicit StateEnterTrigger(AlarmControlPanel *alarm_control_panel) : alarm_control_panel_(alarm_control_panel) {
-    alarm_control_panel->add_on_state_callback([this]() {
-      if (this->alarm_control_panel_->get_state() == State)
-        this->trigger();
-    });
-  }
-
- protected:
-  AlarmControlPanel *alarm_control_panel_;
-};
-
-// Type aliases for state-specific triggers
-using TriggeredTrigger = StateEnterTrigger<ACP_STATE_TRIGGERED>;
-using ArmingTrigger = StateEnterTrigger<ACP_STATE_ARMING>;
-using PendingTrigger = StateEnterTrigger<ACP_STATE_PENDING>;
-using ArmedHomeTrigger = StateEnterTrigger<ACP_STATE_ARMED_HOME>;
-using ArmedNightTrigger = StateEnterTrigger<ACP_STATE_ARMED_NIGHT>;
-using ArmedAwayTrigger = StateEnterTrigger<ACP_STATE_ARMED_AWAY>;
-using DisarmedTrigger = StateEnterTrigger<ACP_STATE_DISARMED>;
-
-/// Trigger when leaving TRIGGERED state (alarm cleared)
-class ClearedTrigger : public Trigger<> {
- public:
-  explicit ClearedTrigger(AlarmControlPanel *alarm_control_panel) {
-    alarm_control_panel->add_on_cleared_callback([this]() { this->trigger(); });
-  }
-};
-
-/// Trigger on chime event (zone opened while disarmed)
-class ChimeTrigger : public Trigger<> {
- public:
-  explicit ChimeTrigger(AlarmControlPanel *alarm_control_panel) {
-    alarm_control_panel->add_on_chime_callback([this]() { this->trigger(); });
-  }
-};
-
-/// Trigger on ready state change
-class ReadyTrigger : public Trigger<> {
- public:
-  explicit ReadyTrigger(AlarmControlPanel *alarm_control_panel) {
-    alarm_control_panel->add_on_ready_callback([this]() { this->trigger(); });
-  }
-};
+static_assert(sizeof(StateAnyForwarder) <= sizeof(void *));
+static_assert(std::is_trivially_copyable_v<StateAnyForwarder>);
+static_assert(sizeof(StateEnterForwarder<ACP_STATE_TRIGGERED>) <= sizeof(void *));
+static_assert(std::is_trivially_copyable_v<StateEnterForwarder<ACP_STATE_TRIGGERED>>);
 
 template<typename... Ts> class ArmAwayAction : public Action<Ts...> {
  public:

esphome/components/alpha3/sensor.py

@@ -9,6 +9,10 @@ from esphome.const import (
     CONF_POWER,
     CONF_SPEED,
     CONF_VOLTAGE,
+    DEVICE_CLASS_CURRENT,
+    DEVICE_CLASS_POWER,
+    DEVICE_CLASS_VOLTAGE,
+    STATE_CLASS_MEASUREMENT,
     UNIT_AMPERE,
     UNIT_CUBIC_METER_PER_HOUR,
     UNIT_METER,
@@ -27,26 +31,35 @@ CONFIG_SCHEMA = (
             cv.Optional(CONF_FLOW): sensor.sensor_schema(
                 unit_of_measurement=UNIT_CUBIC_METER_PER_HOUR,
                 accuracy_decimals=2,
+                state_class=STATE_CLASS_MEASUREMENT,
             ),
             cv.Optional(CONF_HEAD): sensor.sensor_schema(
                 unit_of_measurement=UNIT_METER,
                 accuracy_decimals=2,
+                state_class=STATE_CLASS_MEASUREMENT,
             ),
             cv.Optional(CONF_POWER): sensor.sensor_schema(
                 unit_of_measurement=UNIT_WATT,
                 accuracy_decimals=2,
+                device_class=DEVICE_CLASS_POWER,
+                state_class=STATE_CLASS_MEASUREMENT,
             ),
             cv.Optional(CONF_CURRENT): sensor.sensor_schema(
                 unit_of_measurement=UNIT_AMPERE,
                 accuracy_decimals=2,
+                device_class=DEVICE_CLASS_CURRENT,
+                state_class=STATE_CLASS_MEASUREMENT,
             ),
             cv.Optional(CONF_SPEED): sensor.sensor_schema(
                 unit_of_measurement=UNIT_REVOLUTIONS_PER_MINUTE,
                 accuracy_decimals=2,
+                state_class=STATE_CLASS_MEASUREMENT,
             ),
             cv.Optional(CONF_VOLTAGE): sensor.sensor_schema(
                 unit_of_measurement=UNIT_VOLT,
                 accuracy_decimals=2,
+                device_class=DEVICE_CLASS_VOLTAGE,
+                state_class=STATE_CLASS_MEASUREMENT,
             ),
         }
     )

esphome/components/am43/sensor/__init__.py

@@ -8,6 +8,7 @@ from esphome.const import (
     DEVICE_CLASS_BATTERY,
     ENTITY_CATEGORY_DIAGNOSTIC,
     ICON_BRIGHTNESS_5,
+    STATE_CLASS_MEASUREMENT,
     UNIT_PERCENT,
 )
 
@@ -26,11 +27,13 @@ CONFIG_SCHEMA = (
                 device_class=DEVICE_CLASS_BATTERY,
                 accuracy_decimals=0,
                 entity_category=ENTITY_CATEGORY_DIAGNOSTIC,
+                state_class=STATE_CLASS_MEASUREMENT,
             ),
             cv.Optional(CONF_ILLUMINANCE): sensor.sensor_schema(
                 unit_of_measurement=UNIT_PERCENT,
                 icon=ICON_BRIGHTNESS_5,
                 accuracy_decimals=0,
+                state_class=STATE_CLASS_MEASUREMENT,
             ),
         }
     )

esphome/components/analog_threshold/analog_threshold_binary_sensor.h

@@ -19,8 +19,8 @@ class AnalogThresholdBinarySensor : public Component, public binary_sensor::Bina
 
  protected:
   sensor::Sensor *sensor_{nullptr};
-  TemplatableValue<float> upper_threshold_{};
-  TemplatableValue<float> lower_threshold_{};
+  TemplatableFn<float> upper_threshold_{};
+  TemplatableFn<float> lower_threshold_{};
   bool raw_state_{false};  // Pre-filter state for hysteresis logic
 };
 

esphome/components/analog_threshold/binary_sensor.py

@@ -40,10 +40,10 @@ async def to_code(config):
     cg.add(var.set_sensor(sens))
 
     if isinstance(config[CONF_THRESHOLD], dict):
-        lower = await cg.templatable(config[CONF_THRESHOLD][CONF_LOWER], [], float)
-        upper = await cg.templatable(config[CONF_THRESHOLD][CONF_UPPER], [], float)
+        lower = await cg.templatable(config[CONF_THRESHOLD][CONF_LOWER], [], cg.float_)
+        upper = await cg.templatable(config[CONF_THRESHOLD][CONF_UPPER], [], cg.float_)
     else:
-        lower = await cg.templatable(config[CONF_THRESHOLD], [], float)
+        lower = await cg.templatable(config[CONF_THRESHOLD], [], cg.float_)
         upper = lower
     cg.add(var.set_upper_threshold(upper))
     cg.add(var.set_lower_threshold(lower))

esphome/components/api/__init__.py

@@ -301,11 +301,12 @@ CONFIG_SCHEMA = cv.All(
             # Maximum queued send buffers per connection before dropping connection
             # Each buffer uses ~8-12 bytes overhead plus actual message size
             # Platform defaults based on available RAM and typical message rates:
+            # CONF_MAX_SEND_QUEUE defaults are power of 2 for efficient modulo
             cv.SplitDefault(
                 CONF_MAX_SEND_QUEUE,
-                esp8266=5,  # Limited RAM, need to fail fast
+                esp8266=4,  # Limited RAM, need to fail fast
                 esp32=8,  # More RAM, can buffer more
-                rp2040=5,  # Limited RAM
+                rp2040=8,  # Moderate RAM
                 bk72xx=8,  # Moderate RAM
                 nrf52=8,  # Moderate RAM
                 rtl87xx=8,  # Moderate RAM
@@ -454,6 +455,9 @@ async def to_code(config: ConfigType) -> None:
             cg.add_define("USE_API_PLAINTEXT")
         cg.add_define("USE_API_NOISE")
         cg.add_library("esphome/noise-c", "0.1.11")
+        # Enable optimized memzero/memcmp in libsodium instead of volatile byte loops
+        cg.add_build_flag("-DHAVE_WEAK_SYMBOLS=1")
+        cg.add_build_flag("-DHAVE_INLINE_ASM=1")
     else:
         cg.add_define("USE_API_PLAINTEXT")
 

esphome/components/api/api_buffer.h

@@ -44,6 +44,12 @@ class APIBuffer {
     this->reserve(n);
     this->size_ = n;  // no zero-fill
   }
+  /// Reserve capacity for max(reserve_size, new_size) bytes, then set size to new_size.
+  /// Single grow_ check regardless of argument order.
+  inline void reserve_and_resize(size_t reserve_size, size_t new_size) ESPHOME_ALWAYS_INLINE {
+    this->reserve(std::max(reserve_size, new_size));
+    this->size_ = new_size;
+  }
   uint8_t *data() { return this->data_.get(); }
   const uint8_t *data() const { return this->data_.get(); }
   size_t size() const { return this->size_; }

esphome/components/api/api_connection.cpp

@@ -72,6 +72,14 @@ static constexpr uint32_t HANDSHAKE_TIMEOUT_MS = 60000;
 
 static constexpr auto ESPHOME_VERSION_REF = StringRef::from_lit(ESPHOME_VERSION);
 
+// Cross-validate C++ constants against proto max_data_length annotations in api.proto
+static_assert(MAC_ADDRESS_PRETTY_BUFFER_SIZE - 1 == 17,
+              "Update max_data_length for mac_address/bluetooth_mac_address in api.proto");
+static_assert(Application::BUILD_TIME_STR_SIZE - 1 == 25, "Update max_data_length for compilation_time in api.proto");
+static_assert(sizeof(ESPHOME_VERSION) - 1 <= 32, "Update max_data_length for esphome_version in api.proto");
+static_assert(ESPHOME_DEVICE_NAME_MAX_LEN <= 31, "Update max_data_length for name in api.proto");
+static_assert(ESPHOME_FRIENDLY_NAME_MAX_LEN <= 120, "Update max_data_length for friendly_name in api.proto");
+
 static const char *const TAG = "api.connection";
 #ifdef USE_CAMERA
 static const int CAMERA_STOP_STREAM = 5000;
@@ -132,8 +140,6 @@ APIConnection::APIConnection(std::unique_ptr<socket::Socket> sock, APIServer *pa
 #endif
 }
 
-uint32_t APIConnection::get_batch_delay_ms_() const { return this->parent_->get_batch_delay(); }
-
 void APIConnection::start() {
   this->last_traffic_ = App.get_loop_component_start_time();
 
@@ -234,7 +240,7 @@ void APIConnection::loop() {
           this->last_traffic_ = now;
         }
         // read a packet
-        this->read_message(buffer.data_len, buffer.type, buffer.data);
+        this->read_message_(buffer.data_len, buffer.type, buffer.data);
         if (this->flags_.remove)
           return;
       }
@@ -309,6 +315,8 @@ void APIConnection::process_active_iterator_() {
       this->destroy_active_iterator_();
       if (this->flags_.state_subscription) {
         this->begin_iterator_(ActiveIterator::INITIAL_STATE);
+      } else {
+        this->finalize_iterator_sync_();
       }
     } else {
       this->process_iterator_batch_(this->iterator_storage_.list_entities);
@@ -316,21 +324,27 @@ void APIConnection::process_active_iterator_() {
   } else {  // INITIAL_STATE
     if (this->iterator_storage_.initial_state.completed()) {
       this->destroy_active_iterator_();
-      // Process any remaining batched messages immediately
-      if (!this->deferred_batch_.empty()) {
-        this->process_batch_();
-      }
-      // Now that everything is sent, enable immediate sending for future state changes
-      this->flags_.should_try_send_immediately = true;
-      // Release excess memory from buffers that grew during initial sync
-      this->deferred_batch_.release_buffer();
-      this->helper_->release_buffers();
+      this->finalize_iterator_sync_();
     } else {
       this->process_iterator_batch_(this->iterator_storage_.initial_state);
     }
   }
 }
 
+void APIConnection::finalize_iterator_sync_() {
+  // Flush any remaining batched messages immediately so clients
+  // receive completion responses (e.g. ListEntitiesDoneResponse)
+  // without waiting for the batch timer.
+  if (!this->deferred_batch_.empty()) {
+    this->process_batch_();
+  }
+  // Enable immediate sending for future state changes
+  this->flags_.should_try_send_immediately = true;
+  // Release excess memory from buffers that grew during initial sync
+  this->deferred_batch_.release_buffer();
+  this->helper_->release_buffers();
+}
+
 void APIConnection::process_iterator_batch_(ComponentIterator &iterator) {
   size_t initial_size = this->deferred_batch_.size();
   size_t max_batch = this->get_max_batch_size_();
@@ -400,7 +414,7 @@ uint16_t APIConnection::fill_and_encode_entity_info(EntityBase *entity, InfoResp
 #ifdef USE_DEVICES
   msg.device_id = entity->get_device_id();
 #endif
-  return encode_to_buffer(size_fn(&msg), encode_fn, &msg, conn, remaining_size);
+  return encode_to_buffer_slow(size_fn(&msg), encode_fn, &msg, conn, remaining_size);
 }
 
 uint16_t APIConnection::fill_and_encode_entity_info_with_device_class(EntityBase *entity, InfoResponseProtoMessage &msg,
@@ -1465,7 +1479,7 @@ void APIConnection::send_infrared_rf_receive_event(const InfraredRFReceiveEvent
 void APIConnection::on_serial_proxy_configure_request(const SerialProxyConfigureRequest &msg) {
   auto &proxies = App.get_serial_proxies();
   if (msg.instance >= proxies.size()) {
-    ESP_LOGW(TAG, "Serial proxy instance %u out of range (max %u)", msg.instance,
+    ESP_LOGW(TAG, "Serial proxy instance %" PRIu32 " out of range (max %" PRIu32 ")", msg.instance,
              static_cast<uint32_t>(proxies.size()));
     return;
   }
@@ -1476,7 +1490,7 @@ void APIConnection::on_serial_proxy_configure_request(const SerialProxyConfigure
 void APIConnection::on_serial_proxy_write_request(const SerialProxyWriteRequest &msg) {
   auto &proxies = App.get_serial_proxies();
   if (msg.instance >= proxies.size()) {
-    ESP_LOGW(TAG, "Serial proxy instance %u out of range", msg.instance);
+    ESP_LOGW(TAG, "Serial proxy instance %" PRIu32 " out of range", msg.instance);
     return;
   }
   proxies[msg.instance]->write_from_client(msg.data, msg.data_len);
@@ -1485,7 +1499,7 @@ void APIConnection::on_serial_proxy_write_request(const SerialProxyWriteRequest
 void APIConnection::on_serial_proxy_set_modem_pins_request(const SerialProxySetModemPinsRequest &msg) {
   auto &proxies = App.get_serial_proxies();
   if (msg.instance >= proxies.size()) {
-    ESP_LOGW(TAG, "Serial proxy instance %u out of range", msg.instance);
+    ESP_LOGW(TAG, "Serial proxy instance %" PRIu32 " out of range", msg.instance);
     return;
   }
   proxies[msg.instance]->set_modem_pins(msg.line_states);
@@ -1494,7 +1508,7 @@ void APIConnection::on_serial_proxy_set_modem_pins_request(const SerialProxySetM
 void APIConnection::on_serial_proxy_get_modem_pins_request(const SerialProxyGetModemPinsRequest &msg) {
   auto &proxies = App.get_serial_proxies();
   if (msg.instance >= proxies.size()) {
-    ESP_LOGW(TAG, "Serial proxy instance %u out of range", msg.instance);
+    ESP_LOGW(TAG, "Serial proxy instance %" PRIu32 " out of range", msg.instance);
     return;
   }
   SerialProxyGetModemPinsResponse resp{};
@@ -1506,7 +1520,7 @@ void APIConnection::on_serial_proxy_get_modem_pins_request(const SerialProxyGetM
 void APIConnection::on_serial_proxy_request(const SerialProxyRequest &msg) {
   auto &proxies = App.get_serial_proxies();
   if (msg.instance >= proxies.size()) {
-    ESP_LOGW(TAG, "Serial proxy instance %u out of range", msg.instance);
+    ESP_LOGW(TAG, "Serial proxy instance %" PRIu32 " out of range", msg.instance);
     return;
   }
   switch (msg.type) {
@@ -1519,16 +1533,16 @@ void APIConnection::on_serial_proxy_request(const SerialProxyRequest &msg) {
       resp.instance = msg.instance;
       resp.type = enums::SERIAL_PROXY_REQUEST_TYPE_FLUSH;
       switch (proxies[msg.instance]->flush_port()) {
-        case uart::FlushResult::SUCCESS:
+        case uart::UARTFlushResult::UART_FLUSH_RESULT_SUCCESS:
           resp.status = enums::SERIAL_PROXY_STATUS_OK;
           break;
-        case uart::FlushResult::ASSUMED_SUCCESS:
+        case uart::UARTFlushResult::UART_FLUSH_RESULT_ASSUMED_SUCCESS:
           resp.status = enums::SERIAL_PROXY_STATUS_ASSUMED_SUCCESS;
           break;
-        case uart::FlushResult::TIMEOUT:
+        case uart::UARTFlushResult::UART_FLUSH_RESULT_TIMEOUT:
           resp.status = enums::SERIAL_PROXY_STATUS_TIMEOUT;
           break;
-        case uart::FlushResult::FAILED:
+        case uart::UARTFlushResult::UART_FLUSH_RESULT_FAILED:
           resp.status = enums::SERIAL_PROXY_STATUS_ERROR;
           break;
       }
@@ -1536,7 +1550,7 @@ void APIConnection::on_serial_proxy_request(const SerialProxyRequest &msg) {
       break;
     }
     default:
-      ESP_LOGW(TAG, "Unknown serial proxy request type: %u", static_cast<uint32_t>(msg.type));
+      ESP_LOGW(TAG, "Unknown serial proxy request type: %" PRIu32, static_cast<uint32_t>(msg.type));
       break;
   }
 }
@@ -1549,6 +1563,7 @@ uint16_t APIConnection::try_send_infrared_info(EntityBase *entity, APIConnection
   auto *infrared = static_cast<infrared::Infrared *>(entity);
   ListEntitiesInfraredResponse msg;
   msg.capabilities = infrared->get_capability_flags();
+  msg.receiver_frequency = infrared->get_traits().get_receiver_frequency_hz();
   return fill_and_encode_entity_info(infrared, msg, conn, remaining_size);
 }
 #endif
@@ -1717,6 +1732,7 @@ bool APIConnection::send_device_info_response_() {
   static constexpr auto MANUFACTURER = StringRef::from_lit(ESPHOME_MANUFACTURER);
   resp.manufacturer = MANUFACTURER;
 #endif
+  static_assert(sizeof(ESPHOME_MANUFACTURER) - 1 <= 20, "Update max_data_length for manufacturer in api.proto");
 #undef ESPHOME_MANUFACTURER
 
 #ifdef USE_ESP8266
@@ -1994,53 +2010,15 @@ bool APIConnection::send_message_(uint32_t payload_size, uint8_t message_type, M
   size_t write_start = shared_buf.size();
   shared_buf.resize(write_start + payload_size);
   ProtoWriteBuffer buffer{&shared_buf, write_start};
-  encode_fn(msg, buffer);
+  encode_fn(msg, buffer PROTO_ENCODE_DEBUG_INIT(&shared_buf));
   return this->send_buffer(ProtoWriteBuffer{&shared_buf}, message_type);
 }
-// Encodes a message to the buffer and returns the total number of bytes used,
-// including header and footer overhead. Returns 0 if the message doesn't fit.
-uint16_t APIConnection::encode_to_buffer(uint32_t calculated_size, MessageEncodeFn encode_fn, const void *msg,
-                                         APIConnection *conn, uint32_t remaining_size) {
-#ifdef HAS_PROTO_MESSAGE_DUMP
-  if (conn->flags_.log_only_mode) {
-    auto *proto_msg = static_cast<const ProtoMessage *>(msg);
-    DumpBuffer dump_buf;
-    conn->log_send_message_(proto_msg->message_name(), proto_msg->dump_to(dump_buf));
-    return 1;
-  }
-#endif
-  // Cache frame sizes to avoid repeated virtual calls
-  const uint8_t header_padding = conn->helper_->frame_header_padding();
-  const uint8_t footer_size = conn->helper_->frame_footer_size();
+// encode_to_buffer is defined inline in api_connection.h (ESPHOME_ALWAYS_INLINE)
 
-  // Calculate total size with padding for buffer allocation
-  size_t total_calculated_size = calculated_size + header_padding + footer_size;
-
-  // Check if it fits
-  if (total_calculated_size > remaining_size)
-    return 0;  // Doesn't fit
-
-  auto &shared_buf = conn->parent_->get_shared_buffer_ref();
-
-  if (conn->flags_.batch_first_message) {
-    // First message - buffer already prepared by caller, just clear flag
-    conn->flags_.batch_first_message = false;
-  } else {
-    // Batch message second or later
-    // Add padding for previous message footer + this message header
-    size_t current_size = shared_buf.size();
-    shared_buf.reserve(current_size + total_calculated_size);
-    shared_buf.resize(current_size + footer_size + header_padding);
-  }
-
-  // Pre-resize buffer to include payload, then encode through raw pointer
-  size_t write_start = shared_buf.size();
-  shared_buf.resize(write_start + calculated_size);
-  ProtoWriteBuffer buffer{&shared_buf, write_start};
-  encode_fn(msg, buffer);
-
-  // Return total size (header + payload + footer)
-  return static_cast<uint16_t>(header_padding + calculated_size + footer_size);
+// Noinline version for cold paths — single shared copy
+uint16_t APIConnection::encode_to_buffer_slow(uint32_t calculated_size, MessageEncodeFn encode_fn, const void *msg,
+                                              APIConnection *conn, uint32_t remaining_size) {
+  return encode_to_buffer(calculated_size, encode_fn, msg, conn, remaining_size);
 }
 bool APIConnection::send_buffer(ProtoWriteBuffer buffer, uint8_t message_type) {
   const bool is_log_message = (message_type == SubscribeLogsResponse::MESSAGE_TYPE);
@@ -2072,37 +2050,9 @@ void APIConnection::on_fatal_error() {
   this->flags_.remove = true;
 }
 
-void __attribute__((flatten)) APIConnection::DeferredBatch::push_item(const BatchItem &item) { items.push_back(item); }
-
-void APIConnection::DeferredBatch::add_item(EntityBase *entity, uint8_t message_type, uint8_t estimated_size,
-                                            uint8_t aux_data_index) {
-  // Check if we already have a message of this type for this entity
-  // This provides deduplication per entity/message_type combination
-  // O(n) but optimized for RAM and not performance.
-  // Skip deduplication for events - they are edge-triggered, every occurrence matters
-#ifdef USE_EVENT
-  if (message_type != EventResponse::MESSAGE_TYPE)
-#endif
-  {
-    for (const auto &item : items) {
-      if (item.entity == entity && item.message_type == message_type)
-        return;  // Already queued
-    }
-  }
-  // No existing item found (or event), add new one
-  this->push_item({entity, message_type, estimated_size, aux_data_index});
-}
-
-void APIConnection::DeferredBatch::add_item_front(EntityBase *entity, uint8_t message_type, uint8_t estimated_size) {
-  // Add high priority message and swap to front
-  // This avoids expensive vector::insert which shifts all elements
-  // Note: We only ever have one high-priority message at a time (ping OR disconnect)
-  // If we're disconnecting, pings are blocked, so this simple swap is sufficient
-  this->push_item({entity, message_type, estimated_size, AUX_DATA_UNUSED});
-  if (items.size() > 1) {
-    // Swap the new high-priority item to the front
-    std::swap(items.front(), items.back());
-  }
+bool APIConnection::schedule_message_front_(EntityBase *entity, uint8_t message_type, uint8_t estimated_size) {
+  this->deferred_batch_.add_item_front(entity, message_type, estimated_size);
+  return this->schedule_batch_();
 }
 
 bool APIConnection::send_message_smart_(EntityBase *entity, uint8_t message_type, uint8_t estimated_size,
@@ -2195,17 +2145,15 @@ void APIConnection::process_batch_multi_(APIBuffer &shared_buf, size_t num_items
                 "MessageInfo must remain trivially destructible with this placement-new approach");
 
   const size_t messages_to_process = std::min(num_items, MAX_MESSAGES_PER_BATCH);
-  const uint8_t frame_overhead = header_padding + footer_size;
 
   // Stack-allocated array for message info
   alignas(MessageInfo) char message_info_storage[MAX_MESSAGES_PER_BATCH * sizeof(MessageInfo)];
   MessageInfo *message_info = reinterpret_cast<MessageInfo *>(message_info_storage);
   size_t items_processed = 0;
   uint16_t remaining_size = std::numeric_limits<uint16_t>::max();
-  // Track where each message's header padding begins in the buffer
-  // For plaintext: this is where the 6-byte header padding starts
-  // For noise: this is where the 7-byte header padding starts
-  // The actual message data follows after the header padding
+  // Track where each message's header begins in the buffer
+  // First message: offset 0 (max padding, may have unused leading bytes)
+  // Subsequent messages: offset points to exact header start (no gaps)
   uint32_t current_offset = 0;
 
   // Process items and encode directly to buffer (up to our limit)
@@ -2221,13 +2169,14 @@ void APIConnection::process_batch_multi_(APIBuffer &shared_buf, size_t num_items
     }
 
     // Message was encoded successfully
-    // payload_size is header_padding + actual payload size + footer_size
-    uint16_t proto_payload_size = payload_size - frame_overhead;
+    // payload_size = header_size + proto_payload_size + footer_size
+    uint16_t proto_payload_size = payload_size - this->batch_header_size_ - footer_size;
     // Use placement new to construct MessageInfo in pre-allocated stack array
     // This avoids default-constructing all MAX_MESSAGES_PER_BATCH elements
     // Explicit destruction is not needed because MessageInfo is trivially destructible,
     // as ensured by the static_assert in its definition.
-    new (&message_info[items_processed++]) MessageInfo(item.message_type, current_offset, proto_payload_size);
+    new (&message_info[items_processed++])
+        MessageInfo(item.message_type, current_offset, proto_payload_size, this->batch_header_size_);
     // After first message, set remaining size to MAX_BATCH_PACKET_SIZE to avoid fragmentation
     if (items_processed == 1) {
       remaining_size = MAX_BATCH_PACKET_SIZE;
@@ -2244,6 +2193,13 @@ void APIConnection::process_batch_multi_(APIBuffer &shared_buf, size_t num_items
       shared_buf.resize(shared_buf.size() + footer_size);
     }
 
+    // Ensure TCP_NODELAY is on before writing batch data.
+    // Log messages enable Nagle (NODELAY off) to coalesce small packets.
+    // Without this, batch data written to the socket sits in LWIP's Nagle
+    // buffer — the remote won't ACK until it sends its own data (e.g. a
+    // ping), which can take 20+ seconds.
+    this->helper_->set_nodelay_for_message(false);
+
     // Send all collected messages
     APIError err = this->helper_->write_protobuf_messages(ProtoWriteBuffer{&shared_buf},
                                                           std::span<const MessageInfo>(message_info, items_processed));
@@ -2277,6 +2233,7 @@ void APIConnection::process_batch_multi_(APIBuffer &shared_buf, size_t num_items
 uint16_t APIConnection::dispatch_message_(const DeferredBatch::BatchItem &item, uint32_t remaining_size,
                                           bool batch_first) {
   this->flags_.batch_first_message = batch_first;
+  this->batch_message_type_ = item.message_type;
 #ifdef USE_EVENT
   // Events need aux_data_index to look up event type from entity
   if (item.message_type == EventResponse::MESSAGE_TYPE) {

esphome/components/api/api_frame_helper.cpp

@@ -100,149 +100,81 @@ const LogString *api_error_to_logstr(APIError err) {
   return LOG_STR("UNKNOWN");
 }
 
-// Default implementation for loop - handles sending buffered data
-APIError APIFrameHelper::loop() {
-  if (this->tx_buf_count_ > 0) {
-    APIError err = try_send_tx_buf_();
-    if (err != APIError::OK && err != APIError::WOULD_BLOCK) {
-      return err;
-    }
-  }
-  return APIError::OK;  // Convert WOULD_BLOCK to OK to avoid connection termination
-}
-
-// Common socket write error handling
-APIError APIFrameHelper::handle_socket_write_error_() {
-  if (errno == EWOULDBLOCK || errno == EAGAIN) {
-    return APIError::WOULD_BLOCK;
-  }
-  HELPER_LOG("Socket write failed with errno %d", errno);
-  this->state_ = State::FAILED;
-  return APIError::SOCKET_WRITE_FAILED;
-}
-
-// Helper method to buffer data from IOVs
-void APIFrameHelper::buffer_data_from_iov_(const struct iovec *iov, int iovcnt, uint16_t total_write_len,
-                                           uint16_t offset) {
-  // Check if queue is full
-  if (this->tx_buf_count_ >= API_MAX_SEND_QUEUE) {
-    HELPER_LOG("Send queue full (%u buffers), dropping connection", this->tx_buf_count_);
-    this->state_ = State::FAILED;
-    return;
-  }
-
-  uint16_t buffer_size = total_write_len - offset;
-  auto &buffer = this->tx_buf_[this->tx_buf_tail_];
-  buffer = std::make_unique<SendBuffer>(SendBuffer{
-      .data = std::make_unique<uint8_t[]>(buffer_size),
-      .size = buffer_size,
-      .offset = 0,
-  });
-
-  uint16_t to_skip = offset;
-  uint16_t write_pos = 0;
-
-  for (int i = 0; i < iovcnt; i++) {
-    if (to_skip >= iov[i].iov_len) {
-      // Skip this entire segment
-      to_skip -= static_cast<uint16_t>(iov[i].iov_len);
-    } else {
-      // Include this segment (partially or fully)
-      const uint8_t *src = reinterpret_cast<uint8_t *>(iov[i].iov_base) + to_skip;
-      uint16_t len = static_cast<uint16_t>(iov[i].iov_len) - to_skip;
-      std::memcpy(buffer->data.get() + write_pos, src, len);
-      write_pos += len;
-      to_skip = 0;
-    }
-  }
-
-  // Update circular buffer tracking
-  this->tx_buf_tail_ = (this->tx_buf_tail_ + 1) % API_MAX_SEND_QUEUE;
-  this->tx_buf_count_++;
-}
-
-// This method writes data to socket or buffers it
-APIError APIFrameHelper::write_raw_(const struct iovec *iov, int iovcnt, uint16_t total_write_len) {
-  // Returns APIError::OK if successful (or would block, but data has been buffered)
-  // Returns APIError::SOCKET_WRITE_FAILED if socket write failed, and sets state to FAILED
-
-  if (iovcnt == 0)
-    return APIError::OK;  // Nothing to do, success
-
 #ifdef HELPER_LOG_PACKETS
-  for (int i = 0; i < iovcnt; i++) {
-    LOG_PACKET_SENDING(reinterpret_cast<uint8_t *>(iov[i].iov_base), iov[i].iov_len);
-  }
+void APIFrameHelper::log_packet_sending_(const void *data, uint16_t len) {
+  LOG_PACKET_SENDING(reinterpret_cast<const uint8_t *>(data), len);
+}
 #endif
 
-  // Try to send any existing buffered data first if there is any
-  if (this->tx_buf_count_ > 0) {
-    APIError send_result = try_send_tx_buf_();
-    // If real error occurred (not just WOULD_BLOCK), return it
-    if (send_result != APIError::OK && send_result != APIError::WOULD_BLOCK) {
-      return send_result;
-    }
-
-    // If there is still data in the buffer, we can't send, buffer
-    // the new data and return
-    if (this->tx_buf_count_ > 0) {
-      this->buffer_data_from_iov_(iov, iovcnt, total_write_len, 0);
-      return APIError::OK;  // Success, data buffered
+APIError APIFrameHelper::drain_overflow_and_handle_errors_() {
+  if (this->overflow_buf_.try_drain(this->socket_.get()) == -1) {
+    int err = errno;
+    if (err != EWOULDBLOCK && err != EAGAIN) {
+      this->state_ = State::FAILED;
+      HELPER_LOG("Socket write failed with errno %d", err);
+      return APIError::SOCKET_WRITE_FAILED;
     }
   }
-
-  // Try to send directly if no buffered data
-  // Optimize for single iovec case (common for plaintext API)
-  ssize_t sent =
-      (iovcnt == 1) ? this->socket_->write(iov[0].iov_base, iov[0].iov_len) : this->socket_->writev(iov, iovcnt);
-
-  if (sent == -1) {
-    APIError err = this->handle_socket_write_error_();
-    if (err == APIError::WOULD_BLOCK) {
-      // Socket would block, buffer the data
-      this->buffer_data_from_iov_(iov, iovcnt, total_write_len, 0);
-      return APIError::OK;  // Success, data buffered
-    }
-    return err;  // Socket write failed
-  } else if (static_cast<uint16_t>(sent) < total_write_len) {
-    // Partially sent, buffer the remaining data
-    this->buffer_data_from_iov_(iov, iovcnt, total_write_len, static_cast<uint16_t>(sent));
-  }
-
-  return APIError::OK;  // Success, all data sent or buffered
+  return APIError::OK;
 }
 
-// Common implementation for trying to send buffered data
-// IMPORTANT: Caller MUST ensure tx_buf_count_ > 0 before calling this method
-APIError APIFrameHelper::try_send_tx_buf_() {
-  // Try to send from tx_buf - we assume it's not empty as it's the caller's responsibility to check
-  while (this->tx_buf_count_ > 0) {
-    // Get the first buffer in the queue
-    SendBuffer *front_buffer = this->tx_buf_[this->tx_buf_head_].get();
+// Single-buffer write path: wraps in iovec and delegates.
+APIError APIFrameHelper::write_raw_buf_(const void *data, uint16_t len, ssize_t sent) {
+  struct iovec iov = {const_cast<void *>(data), len};
+  APIError err = this->write_raw_iov_(&iov, 1, len, sent);
+#ifdef HELPER_LOG_PACKETS
+  // Log after write/enqueue so re-entrant log sends can't corrupt data before it's sent
+  if (err == APIError::OK)
+    LOG_PACKET_SENDING(reinterpret_cast<const uint8_t *>(data), len);
+#endif
+  return err;
+}
 
-    // Try to send the remaining data in this buffer
-    ssize_t sent = this->socket_->write(front_buffer->current_data(), front_buffer->remaining());
-
-    if (sent == -1) {
-      return this->handle_socket_write_error_();
-    } else if (sent == 0) {
-      // Nothing sent but not an error
-      return APIError::WOULD_BLOCK;
-    } else if (static_cast<uint16_t>(sent) < front_buffer->remaining()) {
-      // Partially sent, update offset
-      // Cast to ensure no overflow issues with uint16_t
-      front_buffer->offset += static_cast<uint16_t>(sent);
-      return APIError::WOULD_BLOCK;  // Stop processing more buffers if we couldn't send a complete buffer
-    } else {
-      // Buffer completely sent, remove it from the queue
-      this->tx_buf_[this->tx_buf_head_].reset();
-      this->tx_buf_head_ = (this->tx_buf_head_ + 1) % API_MAX_SEND_QUEUE;
-      this->tx_buf_count_--;
-      // Continue loop to try sending the next buffer
+// Handles partial writes, errors, and overflow buffering.
+// Called when the inline fast path couldn't complete the write,
+// or directly from cold paths (handshake, error handling).
+APIError APIFrameHelper::write_raw_iov_(const struct iovec *iov, int iovcnt, uint16_t total_write_len, ssize_t sent) {
+  if (sent <= 0) {
+    if (sent == WRITE_NOT_ATTEMPTED) {
+      // Cold path: no write attempted yet, drain overflow and try
+      if (!this->overflow_buf_.empty()) {
+        APIError err = this->drain_overflow_and_handle_errors_();
+        if (err != APIError::OK)
+          return err;
+      }
+      if (this->overflow_buf_.empty()) {
+        sent = this->write_iov_to_socket_(iov, iovcnt);
+        if (sent == static_cast<ssize_t>(total_write_len))
+          return APIError::OK;
+        // Partial write or -1: fall through to error check / enqueue below
+      } else {
+        // Overflow backlog remains after drain; skip socket write, enqueue everything
+        sent = 0;
+      }
+    }
+    // WRITE_FAILED (-1): fast path or retry write returned -1, check errno
+    if (sent == WRITE_FAILED) {
+      int err = errno;
+      if (err != EWOULDBLOCK && err != EAGAIN) {
+        this->state_ = State::FAILED;
+        HELPER_LOG("Socket write failed with errno %d", err);
+        return APIError::SOCKET_WRITE_FAILED;
+      }
+      sent = 0;  // Treat WOULD_BLOCK as zero bytes sent
     }
   }
 
-  return APIError::OK;  // All buffers sent successfully
+  // Full write completed (possible when called directly, not via write_raw_fast_buf_)
+  if (sent == static_cast<ssize_t>(total_write_len))
+    return APIError::OK;
+
+  // Queue unsent data into overflow buffer
+  if (!this->overflow_buf_.enqueue_iov(iov, iovcnt, total_write_len, static_cast<uint16_t>(sent))) {
+    HELPER_LOG("Overflow buffer full, dropping connection");
+    this->state_ = State::FAILED;
+    return APIError::SOCKET_WRITE_FAILED;
+  }
+  return APIError::OK;
 }
 
 const char *APIFrameHelper::get_peername_to(std::span<char, socket::SOCKADDR_STR_LEN> buf) const {
@@ -278,11 +210,12 @@ APIError APIFrameHelper::init_common_() {
 
 APIError APIFrameHelper::handle_socket_read_result_(ssize_t received) {
   if (received == -1) {
-    if (errno == EWOULDBLOCK || errno == EAGAIN) {
+    const int err = errno;
+    if (err == EWOULDBLOCK || err == EAGAIN) {
       return APIError::WOULD_BLOCK;
     }
     state_ = State::FAILED;
-    HELPER_LOG("Socket read failed with errno %d", errno);
+    HELPER_LOG("Socket read failed with errno %d", err);
     return APIError::SOCKET_READ_FAILED;
   } else if (received == 0) {
     state_ = State::FAILED;

esphome/components/api/api_frame_helper.h

@@ -9,9 +9,11 @@
 #include "esphome/core/defines.h"
 #ifdef USE_API
 #include "esphome/components/api/api_buffer.h"
+#include "esphome/components/api/api_overflow_buffer.h"
 #include "esphome/components/socket/socket.h"
 #include "esphome/core/application.h"
 #include "esphome/core/log.h"
+#include "proto.h"
 
 namespace esphome::api {
 
@@ -37,8 +39,6 @@ static constexpr uint16_t RX_BUF_NULL_TERMINATOR = 1;
 // Must be >= MAX_INITIAL_PER_BATCH in api_connection.h (enforced by static_assert there)
 static constexpr size_t MAX_MESSAGES_PER_BATCH = 34;
 
-class ProtoWriteBuffer;
-
 // Max client name length (e.g., "Home Assistant 2026.1.0.dev0" = 28 chars)
 static constexpr size_t CLIENT_INFO_NAME_MAX_LEN = 32;
 
@@ -49,12 +49,17 @@ struct ReadPacketBuffer {
 };
 
 // Packed message info structure to minimize memory usage
+// Note: message_type is uint8_t — all current protobuf message types fit in 8 bits.
+// The noise wire format encodes types as 16-bit, but the high byte is always 0.
+// If message types ever exceed 255, this and encrypt_noise_message_ must be updated.
 struct MessageInfo {
   uint16_t offset;        // Offset in buffer where message starts
   uint16_t payload_size;  // Size of the message payload
   uint8_t message_type;   // Message type (0-255)
+  uint8_t header_size;    // Actual header size used (avoids recomputation in write path)
 
-  MessageInfo(uint8_t type, uint16_t off, uint16_t size) : offset(off), payload_size(size), message_type(type) {}
+  MessageInfo(uint8_t type, uint16_t off, uint16_t size, uint8_t hdr)
+      : offset(off), payload_size(size), message_type(type), header_size(hdr) {}
 };
 
 enum class APIError : uint16_t {
@@ -105,9 +110,9 @@ class APIFrameHelper {
   }
   virtual ~APIFrameHelper() = default;
   virtual APIError init() = 0;
-  virtual APIError loop();
+  virtual APIError loop() = 0;
   virtual APIError read_packet(ReadPacketBuffer *buffer) = 0;
-  bool can_write_without_blocking() { return this->state_ == State::DATA && this->tx_buf_count_ == 0; }
+  bool can_write_without_blocking() { return this->state_ == State::DATA && this->overflow_buf_.empty(); }
   int getpeername(struct sockaddr *addr, socklen_t *addrlen) { return socket_->getpeername(addr, addrlen); }
   APIError close() {
     if (state_ == State::CLOSED)
@@ -147,31 +152,47 @@ class APIFrameHelper {
   //
   void set_nodelay_for_message(bool is_log_message) {
     if (!is_log_message) {
-      if (this->nodelay_state_ != NODELAY_ON) {
+      if (this->nodelay_counter_) {
         this->set_nodelay_raw_(true);
-        this->nodelay_state_ = NODELAY_ON;
+        this->nodelay_counter_ = 0;
       }
       return;
     }
-
-    // Log messages: state transitions -1 -> 1 -> ... -> LOG_NAGLE_COUNT -> -1 (flush)
-    if (this->nodelay_state_ == NODELAY_ON) {
+    // Log message: enable Nagle on first, flush after LOG_NAGLE_COUNT
+    if (!this->nodelay_counter_)
       this->set_nodelay_raw_(false);
-      this->nodelay_state_ = 1;
-    } else if (this->nodelay_state_ >= LOG_NAGLE_COUNT) {
+    if (++this->nodelay_counter_ > LOG_NAGLE_COUNT) {
       this->set_nodelay_raw_(true);
-      this->nodelay_state_ = NODELAY_ON;
-    } else {
-      this->nodelay_state_++;
+      this->nodelay_counter_ = 0;
     }
   }
+  // Write a single protobuf message - the hot path (87-100% of all writes).
+  // Caller must ensure state is DATA before calling.
   virtual APIError write_protobuf_packet(uint8_t type, ProtoWriteBuffer buffer) = 0;
-  // Write multiple protobuf messages in a single operation
-  // messages contains (message_type, offset, length) for each message in the buffer
-  // The buffer contains all messages with appropriate padding before each
+  // Write multiple protobuf messages in a single batched operation.
+  // Caller must ensure state is DATA and messages is not empty.
+  // messages contains (message_type, offset, length) for each message in the buffer.
+  // The buffer contains all messages with appropriate padding before each.
   virtual APIError write_protobuf_messages(ProtoWriteBuffer buffer, std::span<const MessageInfo> messages) = 0;
-  // Get the frame header padding required by this protocol
+  // Get the maximum frame header padding required by this protocol (worst case)
   uint8_t frame_header_padding() const { return frame_header_padding_; }
+  // Get the actual frame header size for a specific message.
+  // For noise: always returns frame_header_padding_ (fixed 7-byte header).
+  // For plaintext: computes actual size from varint lengths (3-6 bytes).
+  // Distinguishes protocols via frame_footer_size_ (noise always has a non-zero MAC
+  // footer, plaintext has footer=0). If a protocol with a plaintext footer is ever
+  // added, this should become a virtual method.
+  uint8_t frame_header_size(uint16_t payload_size, uint8_t message_type) const {
+#if defined(USE_API_NOISE) && defined(USE_API_PLAINTEXT)
+    return this->frame_footer_size_
+               ? this->frame_header_padding_
+               : static_cast<uint8_t>(1 + ProtoSize::varint16(payload_size) + ProtoSize::varint8(message_type));
+#elif defined(USE_API_NOISE)
+    return this->frame_header_padding_;
+#else  // USE_API_PLAINTEXT only
+    return static_cast<uint8_t>(1 + ProtoSize::varint16(payload_size) + ProtoSize::varint8(message_type));
+#endif
+  }
   // Get the frame footer size required by this protocol
   uint8_t frame_footer_size() const { return frame_footer_size_; }
   // Check if socket has data ready to read
@@ -187,28 +208,46 @@ class APIFrameHelper {
   }
 
  protected:
-  // Buffer containing data to be sent
-  struct SendBuffer {
-    std::unique_ptr<uint8_t[]> data;
-    uint16_t size{0};    // Total size of the buffer
-    uint16_t offset{0};  // Current offset within the buffer
+  // Drain backlogged overflow data to the socket and handle errors.
+  // Called when overflow_buf_.empty() is false. Out-of-line to keep the
+  // fast path (empty check) inline at call sites.
+  // Returns OK for transient errors (WOULD_BLOCK), SOCKET_WRITE_FAILED for hard errors.
+  APIError drain_overflow_and_handle_errors_();
 
-    // Using uint16_t reduces memory usage since ESPHome API messages are limited to UINT16_MAX (65535) bytes
-    uint16_t remaining() const { return size - offset; }
-    const uint8_t *current_data() const { return data.get() + offset; }
-  };
+  // Sentinel values for the sent parameter in write_raw_ methods
+  static constexpr ssize_t WRITE_FAILED = -1;         // Fast path: write()/writev() returned -1
+  static constexpr ssize_t WRITE_NOT_ATTEMPTED = -2;  // Cold path: no write attempted yet
 
-  // Common implementation for writing raw data to socket
-  APIError write_raw_(const struct iovec *iov, int iovcnt, uint16_t total_write_len);
+  // Dispatch to write() or writev() based on iovec count
+  inline ssize_t ESPHOME_ALWAYS_INLINE write_iov_to_socket_(const struct iovec *iov, int iovcnt) {
+    return (iovcnt == 1) ? this->socket_->write(iov[0].iov_base, iov[0].iov_len) : this->socket_->writev(iov, iovcnt);
+  }
 
-  // Try to send data from the tx buffer
-  APIError try_send_tx_buf_();
-
-  // Helper method to buffer data from IOVs
-  void buffer_data_from_iov_(const struct iovec *iov, int iovcnt, uint16_t total_write_len, uint16_t offset);
-
-  // Common socket write error handling
-  APIError handle_socket_write_error_();
+  // Inlined write methods — used by hot paths (write_protobuf_packet, write_protobuf_messages)
+  // These inline the fast path (overflow empty + full write) and tail-call the out-of-line
+  // slow path only on failure/partial write.
+  inline APIError ESPHOME_ALWAYS_INLINE write_raw_fast_buf_(const void *data, uint16_t len) {
+    if (this->overflow_buf_.empty()) [[likely]] {
+      ssize_t sent = this->socket_->write(data, len);
+      if (sent == static_cast<ssize_t>(len)) [[likely]] {
+#ifdef HELPER_LOG_PACKETS
+        this->log_packet_sending_(data, len);
+#endif
+        return APIError::OK;
+      }
+      // sent is -1 (WRITE_FAILED) or partial write count
+      return this->write_raw_buf_(data, len, sent);
+    }
+    return this->write_raw_buf_(data, len, WRITE_NOT_ATTEMPTED);
+  }
+  // Out-of-line write paths: handle partial writes, errors, overflow buffering
+  // sent: WRITE_NOT_ATTEMPTED (cold path), WRITE_FAILED (fast path write returned -1), or bytes sent (partial write)
+  APIError write_raw_buf_(const void *data, uint16_t len, ssize_t sent = WRITE_NOT_ATTEMPTED);
+  APIError write_raw_iov_(const struct iovec *iov, int iovcnt, uint16_t total_write_len,
+                          ssize_t sent = WRITE_NOT_ATTEMPTED);
+#ifdef HELPER_LOG_PACKETS
+  void log_packet_sending_(const void *data, uint16_t len);
+#endif
 
   // Socket ownership (4 bytes on 32-bit, 8 bytes on 64-bit)
   std::unique_ptr<socket::Socket> socket_;
@@ -243,8 +282,8 @@ class APIFrameHelper {
     return APIError::WOULD_BLOCK;
   }
 
-  // Containers (size varies, but typically 12+ bytes on 32-bit)
-  std::array<std::unique_ptr<SendBuffer>, API_MAX_SEND_QUEUE> tx_buf_;
+  // Backlog for unsent data when TCP send buffer is full (rarely used in production)
+  APIOverflowBuffer overflow_buf_;
   APIBuffer rx_buf_;
 
   // Client name buffer - stores name from Hello message or initial peername
@@ -255,21 +294,17 @@ class APIFrameHelper {
   State state_{State::INITIALIZE};
   uint8_t frame_header_padding_{0};
   uint8_t frame_footer_size_{0};
-  uint8_t tx_buf_head_{0};
-  uint8_t tx_buf_tail_{0};
-  uint8_t tx_buf_count_{0};
-  // Nagle batching state for log messages. NODELAY_ON (-1) means NODELAY is enabled
-  // (immediate send). Values 1..LOG_NAGLE_COUNT count log messages in the current Nagle batch.
-  // After LOG_NAGLE_COUNT logs, we switch to NODELAY to flush and reset.
+  // Nagle batching counter for log messages. 0 means NODELAY is enabled (immediate send).
+  // Values 1..LOG_NAGLE_COUNT count log messages in the current Nagle batch.
+  // After LOG_NAGLE_COUNT logs, we flush by re-enabling NODELAY and resetting to 0.
   // ESP8266 has the tightest TCP send buffer (2×MSS) and needs conservative batching.
   // ESP32 (4×MSS+), RP2040 (8×MSS), and LibreTiny (4×MSS) can coalesce more.
-  static constexpr int8_t NODELAY_ON = -1;
 #ifdef USE_ESP8266
-  static constexpr int8_t LOG_NAGLE_COUNT = 2;
+  static constexpr uint8_t LOG_NAGLE_COUNT = 2;
 #else
-  static constexpr int8_t LOG_NAGLE_COUNT = 3;
+  static constexpr uint8_t LOG_NAGLE_COUNT = 3;
 #endif
-  int8_t nodelay_state_{NODELAY_ON};
+  uint8_t nodelay_counter_{0};
 
   // Internal helper to set TCP_NODELAY socket option
   void set_nodelay_raw_(bool enable) {

esphome/components/api/api_frame_helper_noise.cpp

@@ -47,15 +47,8 @@ static constexpr size_t API_MAX_LOG_BYTES = 168;
               format_hex_pretty_to(hex_buf_, (buffer).data(), \
                                    (buffer).size() < API_MAX_LOG_BYTES ? (buffer).size() : API_MAX_LOG_BYTES)); \
   } while (0)
-#define LOG_PACKET_SENDING(data, len) \
-  do { \
-    char hex_buf_[format_hex_pretty_size(API_MAX_LOG_BYTES)]; \
-    ESP_LOGVV(TAG, "Sending raw: %s", \
-              format_hex_pretty_to(hex_buf_, data, (len) < API_MAX_LOG_BYTES ? (len) : API_MAX_LOG_BYTES)); \
-  } while (0)
 #else
 #define LOG_PACKET_RECEIVED(buffer) ((void) 0)
-#define LOG_PACKET_SENDING(data, len) ((void) 0)
 #endif
 
 /// Convert a noise error code to a readable error
@@ -153,8 +146,10 @@ APIError APINoiseFrameHelper::loop() {
     }
   }
 
-  // Use base class implementation for buffer sending
-  return APIFrameHelper::loop();
+  if (!this->overflow_buf_.empty()) [[unlikely]] {
+    return this->drain_overflow_and_handle_errors_();
+  }
+  return APIError::OK;
 }
 
 /** Read a packet into the rx_buf_.
@@ -242,132 +237,144 @@ APIError APINoiseFrameHelper::try_read_frame_() {
  * If an error occurred, returns that error. Only returns OK if the transport is ready for data
  * traffic.
  */
+// Split into per-state methods so the compiler doesn't allocate stack space
+// for all branches simultaneously. On RP2040 the core0 stack lives in a 4KB
+// scratch RAM bank; the Noise crypto path (curve25519) needs ~2KB+ of stack,
+// so every byte saved in the caller matters.
 APIError APINoiseFrameHelper::state_action_() {
-  int err;
-  APIError aerr;
-  if (state_ == State::INITIALIZE) {
-    HELPER_LOG("Bad state for method: %d", (int) state_);
-    return APIError::BAD_STATE;
+  switch (this->state_) {
+    case State::INITIALIZE:
+      HELPER_LOG("Bad state for method: %d", (int) this->state_);
+      return APIError::BAD_STATE;
+    case State::CLIENT_HELLO:
+      return this->state_action_client_hello_();
+    case State::SERVER_HELLO:
+      return this->state_action_server_hello_();
+    case State::HANDSHAKE:
+      return this->state_action_handshake_();
+    case State::CLOSED:
+    case State::FAILED:
+      return APIError::BAD_STATE;
+    default:
+      return APIError::OK;
   }
-  if (state_ == State::CLIENT_HELLO) {
-    // waiting for client hello
-    aerr = this->try_read_frame_();
-    if (aerr != APIError::OK) {
-      return handle_handshake_frame_error_(aerr);
-    }
-    // ignore contents, may be used in future for flags
-    // Resize for: existing prologue + 2 size bytes + frame data
-    size_t old_size = this->prologue_.size();
-    size_t rx_size = this->rx_buf_.size();
-    this->prologue_.resize(old_size + 2 + rx_size);
-    this->prologue_[old_size] = (uint8_t) (rx_size >> 8);
-    this->prologue_[old_size + 1] = (uint8_t) rx_size;
-    if (rx_size > 0) {
-      std::memcpy(this->prologue_.data() + old_size + 2, this->rx_buf_.data(), rx_size);
-    }
-
-    state_ = State::SERVER_HELLO;
+}
+APIError APINoiseFrameHelper::state_action_client_hello_() {
+  // waiting for client hello
+  APIError aerr = this->try_read_frame_();
+  if (aerr != APIError::OK) {
+    return handle_handshake_frame_error_(aerr);
   }
-  if (state_ == State::SERVER_HELLO) {
-    // send server hello
-    const auto &name = App.get_name();
-    char mac[MAC_ADDRESS_BUFFER_SIZE];
-    get_mac_address_into_buffer(mac);
-
-    // Calculate positions and sizes
-    size_t name_len = name.size() + 1;  // including null terminator
-    size_t name_offset = 1;
-    size_t mac_offset = name_offset + name_len;
-    size_t total_size = 1 + name_len + MAC_ADDRESS_BUFFER_SIZE;
-
-    // 1 (proto) + name (max ESPHOME_DEVICE_NAME_MAX_LEN) + 1 (name null)
-    // + mac (MAC_ADDRESS_BUFFER_SIZE - 1) + 1 (mac null)
-    constexpr size_t max_msg_size = 1 + ESPHOME_DEVICE_NAME_MAX_LEN + 1 + MAC_ADDRESS_BUFFER_SIZE;
-    uint8_t msg[max_msg_size];
-
-    // chosen proto
-    msg[0] = 0x01;
-
-    // node name, terminated by null byte
-    std::memcpy(msg + name_offset, name.c_str(), name_len);
-    // node mac, terminated by null byte
-    std::memcpy(msg + mac_offset, mac, MAC_ADDRESS_BUFFER_SIZE);
-
-    aerr = write_frame_(msg, total_size);
-    if (aerr != APIError::OK)
-      return aerr;
-
-    // start handshake
-    aerr = init_handshake_();
-    if (aerr != APIError::OK)
-      return aerr;
-
-    state_ = State::HANDSHAKE;
+  // ignore contents, may be used in future for flags
+  // Resize for: existing prologue + 2 size bytes + frame data
+  size_t old_size = this->prologue_.size();
+  size_t rx_size = this->rx_buf_.size();
+  this->prologue_.resize(old_size + 2 + rx_size);
+  this->prologue_[old_size] = (uint8_t) (rx_size >> 8);
+  this->prologue_[old_size + 1] = (uint8_t) rx_size;
+  if (rx_size > 0) {
+    std::memcpy(this->prologue_.data() + old_size + 2, this->rx_buf_.data(), rx_size);
   }
-  if (state_ == State::HANDSHAKE) {
-    int action = noise_handshakestate_get_action(handshake_);
-    if (action == NOISE_ACTION_READ_MESSAGE) {
-      // waiting for handshake msg
-      aerr = this->try_read_frame_();
-      if (aerr != APIError::OK) {
-        return handle_handshake_frame_error_(aerr);
-      }
 
-      if (this->rx_buf_.empty()) {
-        send_explicit_handshake_reject_(LOG_STR("Empty handshake message"));
-        return APIError::BAD_HANDSHAKE_ERROR_BYTE;
-      } else if (this->rx_buf_[0] != 0x00) {
-        HELPER_LOG("Bad handshake error byte: %u", this->rx_buf_[0]);
-        send_explicit_handshake_reject_(LOG_STR("Bad handshake error byte"));
-        return APIError::BAD_HANDSHAKE_ERROR_BYTE;
-      }
-
-      NoiseBuffer mbuf;
-      noise_buffer_init(mbuf);
-      noise_buffer_set_input(mbuf, this->rx_buf_.data() + 1, this->rx_buf_.size() - 1);
-      err = noise_handshakestate_read_message(handshake_, &mbuf, nullptr);
-      if (err != 0) {
-        // Special handling for MAC failure
-        send_explicit_handshake_reject_(err == NOISE_ERROR_MAC_FAILURE ? LOG_STR("Handshake MAC failure")
-                                                                       : LOG_STR("Handshake error"));
-        return handle_noise_error_(err, LOG_STR("noise_handshakestate_read_message"),
-                                   APIError::HANDSHAKESTATE_READ_FAILED);
-      }
-
-      aerr = check_handshake_finished_();
-      if (aerr != APIError::OK)
-        return aerr;
-    } else if (action == NOISE_ACTION_WRITE_MESSAGE) {
-      uint8_t buffer[65];
-      NoiseBuffer mbuf;
-      noise_buffer_init(mbuf);
-      noise_buffer_set_output(mbuf, buffer + 1, sizeof(buffer) - 1);
-
-      err = noise_handshakestate_write_message(handshake_, &mbuf, nullptr);
-      APIError aerr_write = handle_noise_error_(err, LOG_STR("noise_handshakestate_write_message"),
-                                                APIError::HANDSHAKESTATE_WRITE_FAILED);
-      if (aerr_write != APIError::OK)
-        return aerr_write;
-      buffer[0] = 0x00;  // success
-
-      aerr = write_frame_(buffer, mbuf.size + 1);
-      if (aerr != APIError::OK)
-        return aerr;
-      aerr = check_handshake_finished_();
-      if (aerr != APIError::OK)
-        return aerr;
-    } else {
-      // bad state for action
-      state_ = State::FAILED;
-      HELPER_LOG("Bad action for handshake: %d", action);
-      return APIError::HANDSHAKESTATE_BAD_STATE;
-    }
-  }
-  if (state_ == State::CLOSED || state_ == State::FAILED) {
-    return APIError::BAD_STATE;
-  }
+  state_ = State::SERVER_HELLO;
   return APIError::OK;
 }
+APIError APINoiseFrameHelper::state_action_server_hello_() {
+  // send server hello
+  const auto &name = App.get_name();
+  char mac[MAC_ADDRESS_BUFFER_SIZE];
+  get_mac_address_into_buffer(mac);
+
+  // Calculate positions and sizes
+  size_t name_len = name.size() + 1;  // including null terminator
+  size_t name_offset = 1;
+  size_t mac_offset = name_offset + name_len;
+  size_t total_size = 1 + name_len + MAC_ADDRESS_BUFFER_SIZE;
+
+  // 1 (proto) + name (max ESPHOME_DEVICE_NAME_MAX_LEN) + 1 (name null)
+  // + mac (MAC_ADDRESS_BUFFER_SIZE - 1) + 1 (mac null)
+  constexpr size_t max_msg_size = 1 + ESPHOME_DEVICE_NAME_MAX_LEN + 1 + MAC_ADDRESS_BUFFER_SIZE;
+  uint8_t msg[max_msg_size];
+
+  // chosen proto
+  msg[0] = 0x01;
+
+  // node name, terminated by null byte
+  std::memcpy(msg + name_offset, name.c_str(), name_len);
+  // node mac, terminated by null byte
+  std::memcpy(msg + mac_offset, mac, MAC_ADDRESS_BUFFER_SIZE);
+
+  APIError aerr = write_frame_(msg, total_size);
+  if (aerr != APIError::OK)
+    return aerr;
+
+  // start handshake
+  aerr = init_handshake_();
+  if (aerr != APIError::OK)
+    return aerr;
+
+  state_ = State::HANDSHAKE;
+  return APIError::OK;
+}
+APIError APINoiseFrameHelper::state_action_handshake_() {
+  int action = noise_handshakestate_get_action(this->handshake_);
+  if (action == NOISE_ACTION_READ_MESSAGE) {
+    return this->state_action_handshake_read_();
+  } else if (action == NOISE_ACTION_WRITE_MESSAGE) {
+    return this->state_action_handshake_write_();
+  }
+  // bad state for action
+  this->state_ = State::FAILED;
+  HELPER_LOG("Bad action for handshake: %d", action);
+  return APIError::HANDSHAKESTATE_BAD_STATE;
+}
+APIError APINoiseFrameHelper::state_action_handshake_read_() {
+  APIError aerr = this->try_read_frame_();
+  if (aerr != APIError::OK) {
+    return this->handle_handshake_frame_error_(aerr);
+  }
+
+  if (this->rx_buf_.empty()) {
+    this->send_explicit_handshake_reject_(LOG_STR("Empty handshake message"));
+    return APIError::BAD_HANDSHAKE_ERROR_BYTE;
+  } else if (this->rx_buf_[0] != 0x00) {
+    HELPER_LOG("Bad handshake error byte: %u", this->rx_buf_[0]);
+    this->send_explicit_handshake_reject_(LOG_STR("Bad handshake error byte"));
+    return APIError::BAD_HANDSHAKE_ERROR_BYTE;
+  }
+
+  NoiseBuffer mbuf;
+  noise_buffer_init(mbuf);
+  noise_buffer_set_input(mbuf, this->rx_buf_.data() + 1, this->rx_buf_.size() - 1);
+  int err = noise_handshakestate_read_message(this->handshake_, &mbuf, nullptr);
+  if (err != 0) {
+    // Special handling for MAC failure
+    this->send_explicit_handshake_reject_(err == NOISE_ERROR_MAC_FAILURE ? LOG_STR("Handshake MAC failure")
+                                                                         : LOG_STR("Handshake error"));
+    return this->handle_noise_error_(err, LOG_STR("noise_handshakestate_read_message"),
+                                     APIError::HANDSHAKESTATE_READ_FAILED);
+  }
+
+  return this->check_handshake_finished_();
+}
+APIError APINoiseFrameHelper::state_action_handshake_write_() {
+  uint8_t buffer[65];
+  NoiseBuffer mbuf;
+  noise_buffer_init(mbuf);
+  noise_buffer_set_output(mbuf, buffer + 1, sizeof(buffer) - 1);
+
+  int err = noise_handshakestate_write_message(this->handshake_, &mbuf, nullptr);
+  APIError aerr = this->handle_noise_error_(err, LOG_STR("noise_handshakestate_write_message"),
+                                            APIError::HANDSHAKESTATE_WRITE_FAILED);
+  if (aerr != APIError::OK)
+    return aerr;
+  buffer[0] = 0x00;  // success
+
+  aerr = this->write_frame_(buffer, mbuf.size + 1);
+  if (aerr != APIError::OK)
+    return aerr;
+  return this->check_handshake_finished_();
+}
 void APINoiseFrameHelper::send_explicit_handshake_reject_(const LogString *reason) {
   // Max reject message: "Bad handshake packet len" (24) + 1 (failure byte) = 25 bytes
   uint8_t data[32];
@@ -450,73 +457,83 @@ APIError APINoiseFrameHelper::read_packet(ReadPacketBuffer *buffer) {
   buffer->type = type;
   return APIError::OK;
 }
-APIError APINoiseFrameHelper::write_protobuf_packet(uint8_t type, ProtoWriteBuffer buffer) {
-  // Resize to include MAC space (required for Noise encryption)
-  buffer.get_buffer()->resize(buffer.get_buffer()->size() + frame_footer_size_);
-  MessageInfo msg{type, 0,
-                  static_cast<uint16_t>(buffer.get_buffer()->size() - frame_header_padding_ - frame_footer_size_)};
-  return write_protobuf_messages(buffer, std::span<const MessageInfo>(&msg, 1));
-}
+// Encrypt a single noise message in place and return the encrypted frame length.
+// Returns APIError::OK on success.
+APIError APINoiseFrameHelper::encrypt_noise_message_(uint8_t *buf_start, uint16_t payload_size, uint8_t message_type,
+                                                     uint16_t &encrypted_len_out) {
+  // Write noise header
+  buf_start[0] = 0x01;  // indicator
+  // buf_start[1], buf_start[2] to be set after encryption
 
-APIError APINoiseFrameHelper::write_protobuf_messages(ProtoWriteBuffer buffer, std::span<const MessageInfo> messages) {
-  APIError aerr = this->check_data_state_();
+  // Write message header (to be encrypted)
+  constexpr uint8_t msg_offset = 3;
+  buf_start[msg_offset] = static_cast<uint8_t>(message_type >> 8);      // type high byte
+  buf_start[msg_offset + 1] = static_cast<uint8_t>(message_type);       // type low byte
+  buf_start[msg_offset + 2] = static_cast<uint8_t>(payload_size >> 8);  // data_len high byte
+  buf_start[msg_offset + 3] = static_cast<uint8_t>(payload_size);       // data_len low byte
+  // payload data is already in the buffer starting at offset + 7
+
+  // Encrypt the message in place
+  NoiseBuffer mbuf;
+  noise_buffer_init(mbuf);
+  noise_buffer_set_inout(mbuf, buf_start + msg_offset, 4 + payload_size, 4 + payload_size + this->frame_footer_size_);
+
+  int err = noise_cipherstate_encrypt(this->send_cipher_, &mbuf);
+  APIError aerr =
+      this->handle_noise_error_(err, LOG_STR("noise_cipherstate_encrypt"), APIError::CIPHERSTATE_ENCRYPT_FAILED);
   if (aerr != APIError::OK)
     return aerr;
 
-  if (messages.empty()) {
-    return APIError::OK;
-  }
+  // Fill in the encrypted size
+  buf_start[1] = static_cast<uint8_t>(mbuf.size >> 8);
+  buf_start[2] = static_cast<uint8_t>(mbuf.size);
 
+  encrypted_len_out = static_cast<uint16_t>(3 + mbuf.size);  // indicator + size + encrypted data
+  return APIError::OK;
+}
+
+APIError APINoiseFrameHelper::write_protobuf_packet(uint8_t type, ProtoWriteBuffer buffer) {
+#ifdef ESPHOME_DEBUG_API
+  assert(this->state_ == State::DATA);
+#endif
+
+  // Resize buffer to include footer space for Noise MAC
+  if (this->frame_footer_size_)
+    buffer.get_buffer()->resize(buffer.get_buffer()->size() + this->frame_footer_size_);
+
+  uint16_t payload_size =
+      static_cast<uint16_t>(buffer.get_buffer()->size() - HEADER_PADDING - this->frame_footer_size_);
+  uint8_t *buf_start = buffer.get_buffer()->data();
+  uint16_t encrypted_len;
+  APIError aerr = this->encrypt_noise_message_(buf_start, payload_size, type, encrypted_len);
+  if (aerr != APIError::OK)
+    return aerr;
+  return this->write_raw_fast_buf_(buf_start, encrypted_len);
+}
+
+APIError APINoiseFrameHelper::write_protobuf_messages(ProtoWriteBuffer buffer, std::span<const MessageInfo> messages) {
+#ifdef ESPHOME_DEBUG_API
+  assert(this->state_ == State::DATA);
+  assert(!messages.empty());
+#endif
+
+  // Noise messages are already contiguous in the buffer:
+  // HEADER_PADDING (7) exactly matches the fixed header size, and
+  // footer space (16) is consumed by the encryption MAC.
   uint8_t *buffer_data = buffer.get_buffer()->data();
-
-  // Stack-allocated iovec array - no heap allocation
-  StaticVector<struct iovec, MAX_MESSAGES_PER_BATCH> iovs;
+  uint8_t *write_start = buffer_data + messages[0].offset;
   uint16_t total_write_len = 0;
 
-  // We need to encrypt each message in place
   for (const auto &msg : messages) {
-    // The buffer already has padding at offset
     uint8_t *buf_start = buffer_data + msg.offset;
-
-    // Write noise header
-    buf_start[0] = 0x01;  // indicator
-    // buf_start[1], buf_start[2] to be set after encryption
-
-    // Write message header (to be encrypted)
-    constexpr uint8_t msg_offset = 3;
-    buf_start[msg_offset] = static_cast<uint8_t>(msg.message_type >> 8);      // type high byte
-    buf_start[msg_offset + 1] = static_cast<uint8_t>(msg.message_type);       // type low byte
-    buf_start[msg_offset + 2] = static_cast<uint8_t>(msg.payload_size >> 8);  // data_len high byte
-    buf_start[msg_offset + 3] = static_cast<uint8_t>(msg.payload_size);       // data_len low byte
-    // payload data is already in the buffer starting at offset + 7
-
-    // Make sure we have space for MAC
-    // The buffer should already have been sized appropriately
-
-    // Encrypt the message in place
-    NoiseBuffer mbuf;
-    noise_buffer_init(mbuf);
-    noise_buffer_set_inout(mbuf, buf_start + msg_offset, 4 + msg.payload_size,
-                           4 + msg.payload_size + frame_footer_size_);
-
-    int err = noise_cipherstate_encrypt(send_cipher_, &mbuf);
-    APIError aerr =
-        handle_noise_error_(err, LOG_STR("noise_cipherstate_encrypt"), APIError::CIPHERSTATE_ENCRYPT_FAILED);
+    uint16_t encrypted_len;
+    APIError aerr = this->encrypt_noise_message_(buf_start, msg.payload_size, msg.message_type, encrypted_len);
     if (aerr != APIError::OK)
       return aerr;
-
-    // Fill in the encrypted size
-    buf_start[1] = static_cast<uint8_t>(mbuf.size >> 8);
-    buf_start[2] = static_cast<uint8_t>(mbuf.size);
-
-    // Add iovec for this encrypted message
-    size_t msg_len = static_cast<size_t>(3 + mbuf.size);  // indicator + size + encrypted data
-    iovs.push_back({buf_start, msg_len});
-    total_write_len += msg_len;
+    total_write_len += encrypted_len;
   }
 
-  // Send all encrypted messages in one writev call
-  return this->write_raw_(iovs.data(), iovs.size(), total_write_len);
+  return this->write_raw_fast_buf_(write_start, total_write_len);
 }
 
 APIError APINoiseFrameHelper::write_frame_(const uint8_t *data, uint16_t len) {
@@ -525,16 +542,16 @@ APIError APINoiseFrameHelper::write_frame_(const uint8_t *data, uint16_t len) {
   header[1] = (uint8_t) (len >> 8);
   header[2] = (uint8_t) len;
 
+  if (len == 0) {
+    return this->write_raw_buf_(header, 3);
+  }
   struct iovec iov[2];
   iov[0].iov_base = header;
   iov[0].iov_len = 3;
-  if (len == 0) {
-    return this->write_raw_(iov, 1, 3);  // Just header
-  }
   iov[1].iov_base = const_cast<uint8_t *>(data);
   iov[1].iov_len = len;
 
-  return this->write_raw_(iov, 2, 3 + len);  // Header + data
+  return this->write_raw_iov_(iov, 2, 3 + len);
 }
 
 /** Initiate the data structures for the handshake.
@@ -600,7 +617,7 @@ APIError APINoiseFrameHelper::check_handshake_finished_() {
   if (aerr != APIError::OK)
     return aerr;
 
-  frame_footer_size_ = noise_cipherstate_get_mac_length(send_cipher_);
+  this->frame_footer_size_ = noise_cipherstate_get_mac_length(send_cipher_);
 
   HELPER_LOG("Handshake complete!");
   noise_handshakestate_free(handshake_);

esphome/components/api/api_frame_helper_noise.h

@@ -9,14 +9,16 @@ namespace esphome::api {
 
 class APINoiseFrameHelper final : public APIFrameHelper {
  public:
+  // Noise header structure:
+  // Pos 0: indicator (0x01)
+  // Pos 1-2: encrypted payload size (16-bit big-endian)
+  // Pos 3-6: encrypted type (16-bit) + data_len (16-bit)
+  // Pos 7+: actual payload data
+  static constexpr uint8_t HEADER_PADDING = 1 + 2 + 2 + 2;  // indicator + size + type + data_len
+
   APINoiseFrameHelper(std::unique_ptr<socket::Socket> socket, APINoiseContext &ctx)
       : APIFrameHelper(std::move(socket)), ctx_(ctx) {
-    // Noise header structure:
-    // Pos 0: indicator (0x01)
-    // Pos 1-2: encrypted payload size (16-bit big-endian)
-    // Pos 3-6: encrypted type (16-bit) + data_len (16-bit)
-    // Pos 7+: actual payload data
-    frame_header_padding_ = 7;
+    frame_header_padding_ = HEADER_PADDING;
   }
   ~APINoiseFrameHelper() override;
   APIError init() override;
@@ -27,8 +29,15 @@ class APINoiseFrameHelper final : public APIFrameHelper {
 
  protected:
   APIError state_action_();
+  APIError state_action_client_hello_();
+  APIError state_action_server_hello_();
+  APIError state_action_handshake_();
+  APIError state_action_handshake_read_();
+  APIError state_action_handshake_write_();
   APIError try_read_frame_();
   APIError write_frame_(const uint8_t *data, uint16_t len);
+  APIError encrypt_noise_message_(uint8_t *buf_start, uint16_t payload_size, uint8_t message_type,
+                                  uint16_t &encrypted_len_out);
   APIError init_handshake_();
   APIError check_handshake_finished_();
   void send_explicit_handshake_reject_(const LogString *reason);

esphome/components/api/api_frame_helper_plaintext.cpp

@@ -39,15 +39,8 @@ static constexpr size_t API_MAX_LOG_BYTES = 168;
               format_hex_pretty_to(hex_buf_, (buffer).data(), \
                                    (buffer).size() < API_MAX_LOG_BYTES ? (buffer).size() : API_MAX_LOG_BYTES)); \
   } while (0)
-#define LOG_PACKET_SENDING(data, len) \
-  do { \
-    char hex_buf_[format_hex_pretty_size(API_MAX_LOG_BYTES)]; \
-    ESP_LOGVV(TAG, "Sending raw: %s", \
-              format_hex_pretty_to(hex_buf_, data, (len) < API_MAX_LOG_BYTES ? (len) : API_MAX_LOG_BYTES)); \
-  } while (0)
 #else
 #define LOG_PACKET_RECEIVED(buffer) ((void) 0)
-#define LOG_PACKET_SENDING(data, len) ((void) 0)
 #endif
 
 /// Initialize the frame helper, returns OK if successful.
@@ -64,8 +57,10 @@ APIError APIPlaintextFrameHelper::loop() {
   if (state_ != State::DATA) {
     return APIError::BAD_STATE;
   }
-  // Use base class implementation for buffer sending
-  return APIFrameHelper::loop();
+  if (!this->overflow_buf_.empty()) [[unlikely]] {
+    return this->drain_overflow_and_handle_errors_();
+  }
+  return APIError::OK;
 }
 
 /** Read a packet into the rx_buf_.
@@ -203,7 +198,6 @@ APIError APIPlaintextFrameHelper::read_packet(ReadPacketBuffer *buffer) {
       // Make sure to tell the remote that we don't
       // understand the indicator byte so it knows
       // we do not support it.
-      struct iovec iov[1];
       // The \x00 first byte is the marker for plaintext.
       //
       // The remote will know how to handle the indicator byte,
@@ -218,14 +212,12 @@ APIError APIPlaintextFrameHelper::read_packet(ReadPacketBuffer *buffer) {
                                                 "Bad indicator byte";
       char msg[INDICATOR_MSG_SIZE];
       memcpy_P(msg, MSG_PROGMEM, INDICATOR_MSG_SIZE);
-      iov[0].iov_base = (void *) msg;
+      this->write_raw_buf_(msg, INDICATOR_MSG_SIZE);
 #else
       static const char MSG[] = "\x00"
                                 "Bad indicator byte";
-      iov[0].iov_base = (void *) MSG;
+      this->write_raw_buf_(MSG, INDICATOR_MSG_SIZE);
 #endif
-      iov[0].iov_len = INDICATOR_MSG_SIZE;
-      this->write_raw_(iov, 1, INDICATOR_MSG_SIZE);
     }
     return aerr;
   }
@@ -235,76 +227,101 @@ APIError APIPlaintextFrameHelper::read_packet(ReadPacketBuffer *buffer) {
   buffer->type = this->rx_header_parsed_type_;
   return APIError::OK;
 }
+
+// Encode a 16-bit varint (1-3 bytes) using pre-computed length.
+ESPHOME_ALWAYS_INLINE static inline void encode_varint_16(uint16_t value, uint8_t varint_len, uint8_t *p) {
+  if (varint_len >= 2) {
+    *p++ = static_cast<uint8_t>(value | 0x80);
+    value >>= 7;
+    if (varint_len == 3) {
+      *p++ = static_cast<uint8_t>(value | 0x80);
+      value >>= 7;
+    }
+  }
+  *p = static_cast<uint8_t>(value);
+}
+
+// Encode an 8-bit varint (1-2 bytes) using pre-computed length.
+ESPHOME_ALWAYS_INLINE static inline void encode_varint_8(uint8_t value, uint8_t varint_len, uint8_t *p) {
+  if (varint_len == 2) {
+    *p++ = static_cast<uint8_t>(value | 0x80);
+    *p = static_cast<uint8_t>(value >> 7);
+  } else {
+    *p = value;
+  }
+}
+
+// Write plaintext header into pre-allocated padding before payload.
+// padding_size: bytes reserved before payload (HEADER_PADDING for first/single msg,
+//               actual header size for contiguous batch messages).
+// Returns the total header length (indicator + varints).
+ESPHOME_ALWAYS_INLINE static inline uint8_t write_plaintext_header(uint8_t *buf_start, uint16_t payload_size,
+                                                                   uint8_t message_type, uint8_t padding_size) {
+  uint8_t size_varint_len = ProtoSize::varint16(payload_size);
+  uint8_t type_varint_len = ProtoSize::varint8(message_type);
+  uint8_t total_header_len = 1 + size_varint_len + type_varint_len;
+
+  // The header is right-justified within the padding so it sits immediately before payload.
+  //
+  // Single/first message (padding_size = HEADER_PADDING = 6):
+  //   Example (small, header=3): [0-2] unused | [3] 0x00 | [4] size | [5] type | [6...] payload
+  //   Example (medium, header=4): [0-1] unused | [2] 0x00 | [3-4] size | [5] type | [6...] payload
+  //   Example (large, header=6):  [0] 0x00 | [1-3] size | [4-5] type | [6...] payload
+  //
+  // Batch messages 2+ (padding_size = actual header size, no unused bytes):
+  //   Example (small, header=3): [0] 0x00 | [1] size | [2] type | [3...] payload
+  //   Example (medium, header=4): [0] 0x00 | [1-2] size | [3] type | [4...] payload
+#ifdef ESPHOME_DEBUG_API
+  assert(padding_size >= total_header_len);
+#endif
+  uint32_t header_offset = padding_size - total_header_len;
+
+  // Write the plaintext header
+  buf_start[header_offset] = 0x00;  // indicator
+
+  // Encode varints directly into buffer using pre-computed lengths
+  encode_varint_16(payload_size, size_varint_len, buf_start + header_offset + 1);
+  encode_varint_8(message_type, type_varint_len, buf_start + header_offset + 1 + size_varint_len);
+
+  return total_header_len;
+}
+
 APIError APIPlaintextFrameHelper::write_protobuf_packet(uint8_t type, ProtoWriteBuffer buffer) {
-  MessageInfo msg{type, 0, static_cast<uint16_t>(buffer.get_buffer()->size() - frame_header_padding_)};
-  return write_protobuf_messages(buffer, std::span<const MessageInfo>(&msg, 1));
+#ifdef ESPHOME_DEBUG_API
+  assert(this->state_ == State::DATA);
+#endif
+
+  uint16_t payload_size = static_cast<uint16_t>(buffer.get_buffer()->size() - HEADER_PADDING);
+  uint8_t *buffer_data = buffer.get_buffer()->data();
+  uint8_t header_len = write_plaintext_header(buffer_data, payload_size, type, HEADER_PADDING);
+  return this->write_raw_fast_buf_(buffer_data + HEADER_PADDING - header_len,
+                                   static_cast<uint16_t>(header_len + payload_size));
 }
 
 APIError APIPlaintextFrameHelper::write_protobuf_messages(ProtoWriteBuffer buffer,
                                                           std::span<const MessageInfo> messages) {
-  APIError aerr = this->check_data_state_();
-  if (aerr != APIError::OK)
-    return aerr;
-
-  if (messages.empty()) {
-    return APIError::OK;
-  }
-
+#ifdef ESPHOME_DEBUG_API
+  assert(this->state_ == State::DATA);
+  assert(!messages.empty());
+#endif
   uint8_t *buffer_data = buffer.get_buffer()->data();
 
-  // Stack-allocated iovec array - no heap allocation
-  StaticVector<struct iovec, MAX_MESSAGES_PER_BATCH> iovs;
-  uint16_t total_write_len = 0;
+  // First message has max padding (header_size = HEADER_PADDING), may have unused leading bytes.
+  // Subsequent messages were encoded with exact header sizes (header_size = actual header len).
+  // write_plaintext_header right-justifies the header within header_size bytes of padding.
+  const auto &first = messages[0];
+  uint8_t *first_start = buffer_data + first.offset;
+  uint8_t header_len = write_plaintext_header(first_start, first.payload_size, first.message_type, HEADER_PADDING);
+  uint8_t *write_start = first_start + HEADER_PADDING - header_len;
+  uint16_t total_len = header_len + first.payload_size;
 
-  for (const auto &msg : messages) {
-    // Calculate varint sizes for header layout
-    uint8_t size_varint_len = api::ProtoSize::varint(static_cast<uint32_t>(msg.payload_size));
-    uint8_t type_varint_len = api::ProtoSize::varint(static_cast<uint32_t>(msg.message_type));
-    uint8_t total_header_len = 1 + size_varint_len + type_varint_len;
-
-    // Calculate where to start writing the header
-    // The header starts at the latest possible position to minimize unused padding
-    //
-    // Example 1 (small values): total_header_len = 3, header_offset = 6 - 3 = 3
-    // [0-2]  - Unused padding
-    // [3]    - 0x00 indicator byte
-    // [4]    - Payload size varint (1 byte, for sizes 0-127)
-    // [5]    - Message type varint (1 byte, for types 0-127)
-    // [6...] - Actual payload data
-    //
-    // Example 2 (medium values): total_header_len = 4, header_offset = 6 - 4 = 2
-    // [0-1]  - Unused padding
-    // [2]    - 0x00 indicator byte
-    // [3-4]  - Payload size varint (2 bytes, for sizes 128-16383)
-    // [5]    - Message type varint (1 byte, for types 0-127)
-    // [6...] - Actual payload data
-    //
-    // Example 3 (large values): total_header_len = 6, header_offset = 6 - 6 = 0
-    // [0]    - 0x00 indicator byte
-    // [1-3]  - Payload size varint (3 bytes, for sizes 16384-2097151)
-    // [4-5]  - Message type varint (2 bytes, for types 128-32767)
-    // [6...] - Actual payload data
-    //
-    // The message starts at offset + frame_header_padding_
-    // So we write the header starting at offset + frame_header_padding_ - total_header_len
-    uint8_t *buf_start = buffer_data + msg.offset;
-    uint32_t header_offset = frame_header_padding_ - total_header_len;
-
-    // Write the plaintext header
-    buf_start[header_offset] = 0x00;  // indicator
-
-    // Encode varints directly into buffer
-    encode_varint_to_buffer(msg.payload_size, buf_start + header_offset + 1);
-    encode_varint_to_buffer(msg.message_type, buf_start + header_offset + 1 + size_varint_len);
-
-    // Add iovec for this message (header + payload)
-    size_t msg_len = static_cast<size_t>(total_header_len + msg.payload_size);
-    iovs.push_back({buf_start + header_offset, msg_len});
-    total_write_len += msg_len;
+  for (size_t i = 1; i < messages.size(); i++) {
+    const auto &msg = messages[i];
+    header_len = write_plaintext_header(buffer_data + msg.offset, msg.payload_size, msg.message_type, msg.header_size);
+    total_len += header_len + msg.payload_size;
   }
 
-  // Send all messages in one writev call
-  return write_raw_(iovs.data(), iovs.size(), total_write_len);
+  return this->write_raw_fast_buf_(write_start, total_len);
 }
 
 }  // namespace esphome::api