From 1b90ccde27407f01051c88e14c114cf6dfa7e987 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Wed, 4 Feb 2026 21:14:25 +0100
Subject: [PATCH] [web_server] Fix ESP8266 watchdog panic by deferring actions
 to main loop

---
 esphome/components/web_server/web_server.cpp | 15 +--------------
 esphome/components/web_server/web_server.h   | 11 +++++------
 2 files changed, 6 insertions(+), 20 deletions(-)

diff --git a/esphome/components/web_server/web_server.cpp b/esphome/components/web_server/web_server.cpp
index d30cb524f4..a3bf1e6b02 100644
--- a/esphome/components/web_server/web_server.cpp
+++ b/esphome/components/web_server/web_server.cpp
@@ -721,11 +721,7 @@ void WebServer::handle_switch_request(AsyncWebServerRequest *request, const UrlM
     }
 
     if (action != SWITCH_ACTION_NONE) {
-#ifdef USE_ESP8266
-      execute_switch_action(obj, action);
-#else
       this->defer([obj, action]() { execute_switch_action(obj, action); });
-#endif
       request->send(200);
     } else {
       request->send(404);
@@ -1645,11 +1641,7 @@ void WebServer::handle_lock_request(AsyncWebServerRequest *request, const UrlMat
     }
 
     if (action != LOCK_ACTION_NONE) {
-#ifdef USE_ESP8266
-      execute_lock_action(obj, action);
-#else
       this->defer([obj, action]() { execute_lock_action(obj, action); });
-#endif
       request->send(200);
     } else {
       request->send(404);
@@ -2015,19 +2007,14 @@ void WebServer::handle_infrared_request(AsyncWebServerRequest *request, const Ur
       return;
     }
 
-#ifdef USE_ESP8266
-    // ESP8266 is single-threaded, call directly
-    call.set_raw_timings_base64url(encoded);
-    call.perform();
-#else
     // Defer to main loop for thread safety. Move encoded string into lambda to ensure
     // it outlives the call - set_raw_timings_base64url stores a pointer, so the string
     // must remain valid until perform() completes.
+    // ESP8266 also needs this because ESPAsyncWebServer callbacks run in "sys" context.
     this->defer([call, encoded = std::move(encoded)]() mutable {
       call.set_raw_timings_base64url(encoded);
       call.perform();
     });
-#endif
 
     request->send(200);
     return;
diff --git a/esphome/components/web_server/web_server.h b/esphome/components/web_server/web_server.h
index 92a5c7edee..224c051ece 100644
--- a/esphome/components/web_server/web_server.h
+++ b/esphome/components/web_server/web_server.h
@@ -42,13 +42,12 @@ using ParamNameType = const __FlashStringHelper *;
 using ParamNameType = const char *;
 #endif
 
-// ESP8266 is single-threaded, so actions can execute directly in request context.
-// Multi-core platforms need to defer to main loop thread for thread safety.
-#ifdef USE_ESP8266
-#define DEFER_ACTION(capture, action) action
-#else
+// All platforms need to defer actions to main loop thread.
+// Multi-core platforms need this for thread safety.
+// ESP8266 needs this because ESPAsyncWebServer callbacks run in "sys" context
+// (SDK system context), not "cont" context (continuation/main loop). Calling
+// yield() from sys context causes a panic in the Arduino core.
 #define DEFER_ACTION(capture, action) this->defer([capture]() mutable { action; })
-#endif
 
 /// Result of matching a URL against an entity
 struct EntityMatchResult {