From 97d6f394dea5b7f5694ae82437efe7c08bb30d72 Mon Sep 17 00:00:00 2001
From: Jesse Hills <3060199+jesserockz@users.noreply.github.com>
Date: Thu, 12 Feb 2026 23:04:18 +1300
Subject: [PATCH 1/8] Bump version to 2026.2.0b1

---
 Doxyfile         | 2 +-
 esphome/const.py | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Doxyfile b/Doxyfile
index efc2f464e3..16516a387f 100644
--- a/Doxyfile
+++ b/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         = 2026.2.0-dev
+PROJECT_NUMBER         = 2026.2.0b1
 
 # 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
diff --git a/esphome/const.py b/esphome/const.py
index 00d8013cc6..3b5cccfb25 100644
--- a/esphome/const.py
+++ b/esphome/const.py
@@ -4,7 +4,7 @@ from enum import Enum
 
 from esphome.enum import StrEnum
 
-__version__ = "2026.2.0-dev"
+__version__ = "2026.2.0b1"
 
 ALLOWED_NAME_CHARS = "abcdefghijklmnopqrstuvwxyz0123456789-_"
 VALID_SUBSTITUTIONS_CHARACTERS = (

From 0e1433329da006a6f58dfc1d5e086d93d743bf07 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Thu, 12 Feb 2026 11:04:23 -0600
Subject: [PATCH 2/8] [api] Extract cold code from APIServer::loop() hot path
 (#13902)

---
 esphome/components/api/api_server.cpp | 130 ++++++++++++++------------
 esphome/components/api/api_server.h   |   5 +
 2 files changed, 74 insertions(+), 61 deletions(-)

diff --git a/esphome/components/api/api_server.cpp b/esphome/components/api/api_server.cpp
index 53b41a5c14..5503cf4db8 100644
--- a/esphome/components/api/api_server.cpp
+++ b/esphome/components/api/api_server.cpp
@@ -117,37 +117,7 @@ void APIServer::setup() {
 void APIServer::loop() {
   // Accept new clients only if the socket exists and has incoming connections
   if (this->socket_ && this->socket_->ready()) {
-    while (true) {
-      struct sockaddr_storage source_addr;
-      socklen_t addr_len = sizeof(source_addr);
-
-      auto sock = this->socket_->accept_loop_monitored((struct sockaddr *) &source_addr, &addr_len);
-      if (!sock)
-        break;
-
-      char peername[socket::SOCKADDR_STR_LEN];
-      sock->getpeername_to(peername);
-
-      // Check if we're at the connection limit
-      if (this->clients_.size() >= this->max_connections_) {
-        ESP_LOGW(TAG, "Max connections (%d), rejecting %s", this->max_connections_, peername);
-        // Immediately close - socket destructor will handle cleanup
-        sock.reset();
-        continue;
-      }
-
-      ESP_LOGD(TAG, "Accept %s", peername);
-
-      auto *conn = new APIConnection(std::move(sock), this);
-      this->clients_.emplace_back(conn);
-      conn->start();
-
-      // First client connected - clear warning and update timestamp
-      if (this->clients_.size() == 1 && this->reboot_timeout_ != 0) {
-        this->status_clear_warning();
-        this->last_connected_ = App.get_loop_component_start_time();
-      }
-    }
+    this->accept_new_connections_();
   }
 
   if (this->clients_.empty()) {
@@ -178,46 +148,84 @@ void APIServer::loop() {
   while (client_index < this->clients_.size()) {
     auto &client = this->clients_[client_index];
 
-    if (!client->flags_.remove) {
+    if (client->flags_.remove) {
+      // Rare case: handle disconnection (don't increment - swapped element needs processing)
+      this->remove_client_(client_index);
+    } else {
       // Common case: process active client
       client->loop();
       client_index++;
+    }
+  }
+}
+
+void APIServer::remove_client_(size_t client_index) {
+  auto &client = this->clients_[client_index];
+
+#ifdef USE_API_USER_DEFINED_ACTION_RESPONSES
+  this->unregister_active_action_calls_for_connection(client.get());
+#endif
+  ESP_LOGV(TAG, "Remove connection %s", client->get_name());
+
+#ifdef USE_API_CLIENT_DISCONNECTED_TRIGGER
+  // Save client info before closing socket and removal for the trigger
+  char peername_buf[socket::SOCKADDR_STR_LEN];
+  std::string client_name(client->get_name());
+  std::string client_peername(client->get_peername_to(peername_buf));
+#endif
+
+  // Close socket now (was deferred from on_fatal_error to allow getpeername)
+  client->helper_->close();
+
+  // Swap with the last element and pop (avoids expensive vector shifts)
+  if (client_index < this->clients_.size() - 1) {
+    std::swap(this->clients_[client_index], this->clients_.back());
+  }
+  this->clients_.pop_back();
+
+  // Last client disconnected - set warning and start tracking for reboot timeout
+  if (this->clients_.empty() && this->reboot_timeout_ != 0) {
+    this->status_set_warning();
+    this->last_connected_ = App.get_loop_component_start_time();
+  }
+
+#ifdef USE_API_CLIENT_DISCONNECTED_TRIGGER
+  // Fire trigger after client is removed so api.connected reflects the true state
+  this->client_disconnected_trigger_.trigger(client_name, client_peername);
+#endif
+}
+
+void APIServer::accept_new_connections_() {
+  while (true) {
+    struct sockaddr_storage source_addr;
+    socklen_t addr_len = sizeof(source_addr);
+
+    auto sock = this->socket_->accept_loop_monitored((struct sockaddr *) &source_addr, &addr_len);
+    if (!sock)
+      break;
+
+    char peername[socket::SOCKADDR_STR_LEN];
+    sock->getpeername_to(peername);
+
+    // Check if we're at the connection limit
+    if (this->clients_.size() >= this->max_connections_) {
+      ESP_LOGW(TAG, "Max connections (%d), rejecting %s", this->max_connections_, peername);
+      // Immediately close - socket destructor will handle cleanup
+      sock.reset();
       continue;
     }
 
-    // Rare case: handle disconnection
-#ifdef USE_API_USER_DEFINED_ACTION_RESPONSES
-    this->unregister_active_action_calls_for_connection(client.get());
-#endif
-    ESP_LOGV(TAG, "Remove connection %s", client->get_name());
+    ESP_LOGD(TAG, "Accept %s", peername);
 
-#ifdef USE_API_CLIENT_DISCONNECTED_TRIGGER
-    // Save client info before closing socket and removal for the trigger
-    char peername_buf[socket::SOCKADDR_STR_LEN];
-    std::string client_name(client->get_name());
-    std::string client_peername(client->get_peername_to(peername_buf));
-#endif
+    auto *conn = new APIConnection(std::move(sock), this);
+    this->clients_.emplace_back(conn);
+    conn->start();
 
-    // Close socket now (was deferred from on_fatal_error to allow getpeername)
-    client->helper_->close();
-
-    // Swap with the last element and pop (avoids expensive vector shifts)
-    if (client_index < this->clients_.size() - 1) {
-      std::swap(this->clients_[client_index], this->clients_.back());
-    }
-    this->clients_.pop_back();
-
-    // Last client disconnected - set warning and start tracking for reboot timeout
-    if (this->clients_.empty() && this->reboot_timeout_ != 0) {
-      this->status_set_warning();
+    // First client connected - clear warning and update timestamp
+    if (this->clients_.size() == 1 && this->reboot_timeout_ != 0) {
+      this->status_clear_warning();
       this->last_connected_ = App.get_loop_component_start_time();
     }
-
-#ifdef USE_API_CLIENT_DISCONNECTED_TRIGGER
-    // Fire trigger after client is removed so api.connected reflects the true state
-    this->client_disconnected_trigger_.trigger(client_name, client_peername);
-#endif
-    // Don't increment client_index since we need to process the swapped element
   }
 }
 
diff --git a/esphome/components/api/api_server.h b/esphome/components/api/api_server.h
index 6ab3cdc576..28f60343e0 100644
--- a/esphome/components/api/api_server.h
+++ b/esphome/components/api/api_server.h
@@ -234,6 +234,11 @@ class APIServer : public Component,
 #endif
 
  protected:
+  // Accept incoming socket connections. Only called when socket has pending connections.
+  void __attribute__((noinline)) accept_new_connections_();
+  // Remove a disconnected client by index. Swaps with last element and pops.
+  void __attribute__((noinline)) remove_client_(size_t client_index);
+
 #ifdef USE_API_NOISE
   bool update_noise_psk_(const SavedNoisePsk &new_psk, const LogString *save_log_msg, const LogString *fail_log_msg,
                          const psk_t &active_psk, bool make_active);

From cde8b6671932d3b75b0a323ef947f24cd9f2872f Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Thu, 12 Feb 2026 11:04:41 -0600
Subject: [PATCH 3/8] [web_server] Switch from getParam to arg API to eliminate
 heap allocations (#13942)

---
 .../captive_portal/captive_portal.cpp         |  8 +-
 esphome/components/web_server/web_server.cpp  | 94 +++++++++----------
 esphome/components/web_server/web_server.h    | 53 ++++-------
 esphome/components/web_server_idf/utils.cpp   | 41 ++++----
 esphome/components/web_server_idf/utils.h     |  5 +-
 .../web_server_idf/web_server_idf.cpp         | 52 ++++++++--
 .../web_server_idf/web_server_idf.h           | 11 +--
 7 files changed, 134 insertions(+), 130 deletions(-)

diff --git a/esphome/components/captive_portal/captive_portal.cpp b/esphome/components/captive_portal/captive_portal.cpp
index 8d88a10b27..5af6ab29a2 100644
--- a/esphome/components/captive_portal/captive_portal.cpp
+++ b/esphome/components/captive_portal/captive_portal.cpp
@@ -47,8 +47,8 @@ void CaptivePortal::handle_config(AsyncWebServerRequest *request) {
   request->send(stream);
 }
 void CaptivePortal::handle_wifisave(AsyncWebServerRequest *request) {
-  std::string ssid = request->arg("ssid").c_str();  // NOLINT(readability-redundant-string-cstr)
-  std::string psk = request->arg("psk").c_str();    // NOLINT(readability-redundant-string-cstr)
+  const auto &ssid = request->arg("ssid");
+  const auto &psk = request->arg("psk");
   ESP_LOGI(TAG,
            "Requested WiFi Settings Change:\n"
            "  SSID='%s'\n"
@@ -56,10 +56,10 @@ void CaptivePortal::handle_wifisave(AsyncWebServerRequest *request) {
            ssid.c_str(), psk.c_str());
 #ifdef USE_ESP8266
   // ESP8266 is single-threaded, call directly
-  wifi::global_wifi_component->save_wifi_sta(ssid, psk);
+  wifi::global_wifi_component->save_wifi_sta(ssid.c_str(), psk.c_str());
 #else
   // Defer save to main loop thread to avoid NVS operations from HTTP thread
-  this->defer([ssid, psk]() { wifi::global_wifi_component->save_wifi_sta(ssid, psk); });
+  this->defer([ssid, psk]() { wifi::global_wifi_component->save_wifi_sta(ssid.c_str(), psk.c_str()); });
 #endif
   request->redirect(ESPHOME_F("/?save"));
 }
diff --git a/esphome/components/web_server/web_server.cpp b/esphome/components/web_server/web_server.cpp
index 7da8b49c6d..c7a0639382 100644
--- a/esphome/components/web_server/web_server.cpp
+++ b/esphome/components/web_server/web_server.cpp
@@ -585,8 +585,7 @@ static void set_json_icon_state_value(JsonObject &root, EntityBase *obj, const c
 
 // Helper to get request detail parameter
 static JsonDetail get_request_detail(AsyncWebServerRequest *request) {
-  auto *param = request->getParam(ESPHOME_F("detail"));
-  return (param && param->value() == "all") ? DETAIL_ALL : DETAIL_STATE;
+  return request->arg(ESPHOME_F("detail")) == "all" ? DETAIL_ALL : DETAIL_STATE;
 }
 
 #ifdef USE_SENSOR
@@ -863,10 +862,10 @@ void WebServer::handle_fan_request(AsyncWebServerRequest *request, const UrlMatc
       }
       auto call = is_on ? obj->turn_on() : obj->turn_off();
 
-      parse_int_param_(request, ESPHOME_F("speed_level"), call, &decltype(call)::set_speed);
+      parse_num_param_(request, ESPHOME_F("speed_level"), call, &decltype(call)::set_speed);
 
-      if (request->hasParam(ESPHOME_F("oscillation"))) {
-        auto speed = request->getParam(ESPHOME_F("oscillation"))->value();
+      if (request->hasArg(ESPHOME_F("oscillation"))) {
+        auto speed = request->arg(ESPHOME_F("oscillation"));
         auto val = parse_on_off(speed.c_str());
         switch (val) {
           case PARSE_ON:
@@ -1042,14 +1041,14 @@ void WebServer::handle_cover_request(AsyncWebServerRequest *request, const UrlMa
     }
 
     auto traits = obj->get_traits();
-    if ((request->hasParam(ESPHOME_F("position")) && !traits.get_supports_position()) ||
-        (request->hasParam(ESPHOME_F("tilt")) && !traits.get_supports_tilt())) {
+    if ((request->hasArg(ESPHOME_F("position")) && !traits.get_supports_position()) ||
+        (request->hasArg(ESPHOME_F("tilt")) && !traits.get_supports_tilt())) {
       request->send(409);
       return;
     }
 
-    parse_float_param_(request, ESPHOME_F("position"), call, &decltype(call)::set_position);
-    parse_float_param_(request, ESPHOME_F("tilt"), call, &decltype(call)::set_tilt);
+    parse_num_param_(request, ESPHOME_F("position"), call, &decltype(call)::set_position);
+    parse_num_param_(request, ESPHOME_F("tilt"), call, &decltype(call)::set_tilt);
 
     DEFER_ACTION(call, call.perform());
     request->send(200);
@@ -1108,7 +1107,7 @@ void WebServer::handle_number_request(AsyncWebServerRequest *request, const UrlM
     }
 
     auto call = obj->make_call();
-    parse_float_param_(request, ESPHOME_F("value"), call, &decltype(call)::set_value);
+    parse_num_param_(request, ESPHOME_F("value"), call, &decltype(call)::set_value);
 
     DEFER_ACTION(call, call.perform());
     request->send(200);
@@ -1176,12 +1175,13 @@ void WebServer::handle_date_request(AsyncWebServerRequest *request, const UrlMat
 
     auto call = obj->make_call();
 
-    if (!request->hasParam(ESPHOME_F("value"))) {
+    const auto &value = request->arg(ESPHOME_F("value"));
+    // Arduino String has isEmpty() not empty(), use length() for cross-platform compatibility
+    if (value.length() == 0) {  // NOLINT(readability-container-size-empty)
       request->send(409);
       return;
     }
-
-    parse_string_param_(request, ESPHOME_F("value"), call, &decltype(call)::set_date);
+    call.set_date(value.c_str(), value.length());
 
     DEFER_ACTION(call, call.perform());
     request->send(200);
@@ -1236,12 +1236,13 @@ void WebServer::handle_time_request(AsyncWebServerRequest *request, const UrlMat
 
     auto call = obj->make_call();
 
-    if (!request->hasParam(ESPHOME_F("value"))) {
+    const auto &value = request->arg(ESPHOME_F("value"));
+    // Arduino String has isEmpty() not empty(), use length() for cross-platform compatibility
+    if (value.length() == 0) {  // NOLINT(readability-container-size-empty)
       request->send(409);
       return;
     }
-
-    parse_string_param_(request, ESPHOME_F("value"), call, &decltype(call)::set_time);
+    call.set_time(value.c_str(), value.length());
 
     DEFER_ACTION(call, call.perform());
     request->send(200);
@@ -1295,12 +1296,13 @@ void WebServer::handle_datetime_request(AsyncWebServerRequest *request, const Ur
 
     auto call = obj->make_call();
 
-    if (!request->hasParam(ESPHOME_F("value"))) {
+    const auto &value = request->arg(ESPHOME_F("value"));
+    // Arduino String has isEmpty() not empty(), use length() for cross-platform compatibility
+    if (value.length() == 0) {  // NOLINT(readability-container-size-empty)
       request->send(409);
       return;
     }
-
-    parse_string_param_(request, ESPHOME_F("value"), call, &decltype(call)::set_datetime);
+    call.set_datetime(value.c_str(), value.length());
 
     DEFER_ACTION(call, call.perform());
     request->send(200);
@@ -1479,10 +1481,14 @@ void WebServer::handle_climate_request(AsyncWebServerRequest *request, const Url
     parse_string_param_(request, ESPHOME_F("swing_mode"), call, &decltype(call)::set_swing_mode);
 
     // Parse temperature parameters
-    parse_float_param_(request, ESPHOME_F("target_temperature_high"), call,
-                       &decltype(call)::set_target_temperature_high);
-    parse_float_param_(request, ESPHOME_F("target_temperature_low"), call, &decltype(call)::set_target_temperature_low);
-    parse_float_param_(request, ESPHOME_F("target_temperature"), call, &decltype(call)::set_target_temperature);
+    // static_cast needed to disambiguate overloaded setters (float vs optional<float>)
+    using ClimateCall = decltype(call);
+    parse_num_param_(request, ESPHOME_F("target_temperature_high"), call,
+                     static_cast<ClimateCall &(ClimateCall::*) (float)>(&ClimateCall::set_target_temperature_high));
+    parse_num_param_(request, ESPHOME_F("target_temperature_low"), call,
+                     static_cast<ClimateCall &(ClimateCall::*) (float)>(&ClimateCall::set_target_temperature_low));
+    parse_num_param_(request, ESPHOME_F("target_temperature"), call,
+                     static_cast<ClimateCall &(ClimateCall::*) (float)>(&ClimateCall::set_target_temperature));
 
     DEFER_ACTION(call, call.perform());
     request->send(200);
@@ -1723,12 +1729,12 @@ void WebServer::handle_valve_request(AsyncWebServerRequest *request, const UrlMa
     }
 
     auto traits = obj->get_traits();
-    if (request->hasParam(ESPHOME_F("position")) && !traits.get_supports_position()) {
+    if (request->hasArg(ESPHOME_F("position")) && !traits.get_supports_position()) {
       request->send(409);
       return;
     }
 
-    parse_float_param_(request, ESPHOME_F("position"), call, &decltype(call)::set_position);
+    parse_num_param_(request, ESPHOME_F("position"), call, &decltype(call)::set_position);
 
     DEFER_ACTION(call, call.perform());
     request->send(200);
@@ -1872,12 +1878,12 @@ void WebServer::handle_water_heater_request(AsyncWebServerRequest *request, cons
     parse_string_param_(request, ESPHOME_F("mode"), base_call, &water_heater::WaterHeaterCall::set_mode);
 
     // Parse temperature parameters
-    parse_float_param_(request, ESPHOME_F("target_temperature"), base_call,
-                       &water_heater::WaterHeaterCall::set_target_temperature);
-    parse_float_param_(request, ESPHOME_F("target_temperature_low"), base_call,
-                       &water_heater::WaterHeaterCall::set_target_temperature_low);
-    parse_float_param_(request, ESPHOME_F("target_temperature_high"), base_call,
-                       &water_heater::WaterHeaterCall::set_target_temperature_high);
+    parse_num_param_(request, ESPHOME_F("target_temperature"), base_call,
+                     &water_heater::WaterHeaterCall::set_target_temperature);
+    parse_num_param_(request, ESPHOME_F("target_temperature_low"), base_call,
+                     &water_heater::WaterHeaterCall::set_target_temperature_low);
+    parse_num_param_(request, ESPHOME_F("target_temperature_high"), base_call,
+                     &water_heater::WaterHeaterCall::set_target_temperature_high);
 
     // Parse away mode parameter
     parse_bool_param_(request, ESPHOME_F("away"), base_call, &water_heater::WaterHeaterCall::set_away);
@@ -1981,16 +1987,16 @@ void WebServer::handle_infrared_request(AsyncWebServerRequest *request, const Ur
     auto call = obj->make_call();
 
     // Parse carrier frequency (optional)
-    if (request->hasParam(ESPHOME_F("carrier_frequency"))) {
-      auto value = parse_number<uint32_t>(request->getParam(ESPHOME_F("carrier_frequency"))->value().c_str());
+    {
+      auto value = parse_number<uint32_t>(request->arg(ESPHOME_F("carrier_frequency")).c_str());
       if (value.has_value()) {
         call.set_carrier_frequency(*value);
       }
     }
 
     // Parse repeat count (optional, defaults to 1)
-    if (request->hasParam(ESPHOME_F("repeat_count"))) {
-      auto value = parse_number<uint32_t>(request->getParam(ESPHOME_F("repeat_count"))->value().c_str());
+    {
+      auto value = parse_number<uint32_t>(request->arg(ESPHOME_F("repeat_count")).c_str());
       if (value.has_value()) {
         call.set_repeat_count(*value);
       }
@@ -1998,18 +2004,12 @@ void WebServer::handle_infrared_request(AsyncWebServerRequest *request, const Ur
 
     // Parse base64url-encoded raw timings (required)
     // Base64url is URL-safe: uses A-Za-z0-9-_ (no special characters needing escaping)
-    if (!request->hasParam(ESPHOME_F("data"))) {
-      request->send(400, ESPHOME_F("text/plain"), ESPHOME_F("Missing 'data' parameter"));
-      return;
-    }
+    const auto &data_arg = request->arg(ESPHOME_F("data"));
 
-    // .c_str() is required for Arduino framework where value() returns Arduino String instead of std::string
-    std::string encoded =
-        request->getParam(ESPHOME_F("data"))->value().c_str();  // NOLINT(readability-redundant-string-cstr)
-
-    // Validate base64url is not empty
-    if (encoded.empty()) {
-      request->send(400, ESPHOME_F("text/plain"), ESPHOME_F("Empty 'data' parameter"));
+    // Validate base64url is not empty (also catches missing parameter since arg() returns empty string)
+    // Arduino String has isEmpty() not empty(), use length() for cross-platform compatibility
+    if (data_arg.length() == 0) {  // NOLINT(readability-container-size-empty)
+      request->send(400, ESPHOME_F("text/plain"), ESPHOME_F("Missing or empty 'data' parameter"));
       return;
     }
 
@@ -2017,7 +2017,7 @@ void WebServer::handle_infrared_request(AsyncWebServerRequest *request, const Ur
     // 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 {
+    this->defer([call, encoded = std::string(data_arg.c_str(), data_arg.length())]() mutable {
       call.set_raw_timings_base64url(encoded);
       call.perform();
     });
diff --git a/esphome/components/web_server/web_server.h b/esphome/components/web_server/web_server.h
index ce09ebf7a9..026da763ea 100644
--- a/esphome/components/web_server/web_server.h
+++ b/esphome/components/web_server/web_server.h
@@ -513,11 +513,9 @@ class WebServer : public Controller,
   template<typename T, typename Ret>
   void parse_light_param_(AsyncWebServerRequest *request, ParamNameType param_name, T &call, Ret (T::*setter)(float),
                           float scale = 1.0f) {
-    if (request->hasParam(param_name)) {
-      auto value = parse_number<float>(request->getParam(param_name)->value().c_str());
-      if (value.has_value()) {
-        (call.*setter)(*value / scale);
-      }
+    auto value = parse_number<float>(request->arg(param_name).c_str());
+    if (value.has_value()) {
+      (call.*setter)(*value / scale);
     }
   }
 
@@ -525,34 +523,19 @@ class WebServer : public Controller,
   template<typename T, typename Ret>
   void parse_light_param_uint_(AsyncWebServerRequest *request, ParamNameType param_name, T &call,
                                Ret (T::*setter)(uint32_t), uint32_t scale = 1) {
-    if (request->hasParam(param_name)) {
-      auto value = parse_number<uint32_t>(request->getParam(param_name)->value().c_str());
-      if (value.has_value()) {
-        (call.*setter)(*value * scale);
-      }
+    auto value = parse_number<uint32_t>(request->arg(param_name).c_str());
+    if (value.has_value()) {
+      (call.*setter)(*value * scale);
     }
   }
 #endif
 
-  // Generic helper to parse and apply a float parameter
-  template<typename T, typename Ret>
-  void parse_float_param_(AsyncWebServerRequest *request, ParamNameType param_name, T &call, Ret (T::*setter)(float)) {
-    if (request->hasParam(param_name)) {
-      auto value = parse_number<float>(request->getParam(param_name)->value().c_str());
-      if (value.has_value()) {
-        (call.*setter)(*value);
-      }
-    }
-  }
-
-  // Generic helper to parse and apply an int parameter
-  template<typename T, typename Ret>
-  void parse_int_param_(AsyncWebServerRequest *request, ParamNameType param_name, T &call, Ret (T::*setter)(int)) {
-    if (request->hasParam(param_name)) {
-      auto value = parse_number<int>(request->getParam(param_name)->value().c_str());
-      if (value.has_value()) {
-        (call.*setter)(*value);
-      }
+  // Generic helper to parse and apply a numeric parameter
+  template<typename NumT, typename T, typename Ret>
+  void parse_num_param_(AsyncWebServerRequest *request, ParamNameType param_name, T &call, Ret (T::*setter)(NumT)) {
+    auto value = parse_number<NumT>(request->arg(param_name).c_str());
+    if (value.has_value()) {
+      (call.*setter)(*value);
     }
   }
 
@@ -560,10 +543,9 @@ class WebServer : public Controller,
   template<typename T, typename Ret>
   void parse_string_param_(AsyncWebServerRequest *request, ParamNameType param_name, T &call,
                            Ret (T::*setter)(const std::string &)) {
-    if (request->hasParam(param_name)) {
-      // .c_str() is required for Arduino framework where value() returns Arduino String instead of std::string
-      std::string value = request->getParam(param_name)->value().c_str();  // NOLINT(readability-redundant-string-cstr)
-      (call.*setter)(value);
+    if (request->hasArg(param_name)) {
+      const auto &value = request->arg(param_name);
+      (call.*setter)(std::string(value.c_str(), value.length()));
     }
   }
 
@@ -573,8 +555,9 @@ class WebServer : public Controller,
   // Invalid values are ignored (setter not called)
   template<typename T, typename Ret>
   void parse_bool_param_(AsyncWebServerRequest *request, ParamNameType param_name, T &call, Ret (T::*setter)(bool)) {
-    if (request->hasParam(param_name)) {
-      auto param_value = request->getParam(param_name)->value();
+    const auto &param_value = request->arg(param_name);
+    // Arduino String has isEmpty() not empty(), use length() for cross-platform compatibility
+    if (param_value.length() > 0) {  // NOLINT(readability-container-size-empty)
       // First check on/off (default), then true/false (custom)
       auto val = parse_on_off(param_value.c_str());
       if (val == PARSE_NONE) {
diff --git a/esphome/components/web_server_idf/utils.cpp b/esphome/components/web_server_idf/utils.cpp
index 81ae626277..c58ca2a24f 100644
--- a/esphome/components/web_server_idf/utils.cpp
+++ b/esphome/components/web_server_idf/utils.cpp
@@ -1,17 +1,13 @@
 #ifdef USE_ESP32
-#include <memory>
 #include <cstring>
 #include <cctype>
 #include "esphome/core/helpers.h"
-#include "esphome/core/log.h"
 #include "http_parser.h"
 
 #include "utils.h"
 
 namespace esphome::web_server_idf {
 
-static const char *const TAG = "web_server_idf_utils";
-
 size_t url_decode(char *str) {
   char *start = str;
   char *ptr = str, buf;
@@ -54,32 +50,15 @@ optional<std::string> request_get_header(httpd_req_t *req, const char *name) {
   return {str};
 }
 
-optional<std::string> request_get_url_query(httpd_req_t *req) {
-  auto len = httpd_req_get_url_query_len(req);
-  if (len == 0) {
-    return {};
-  }
-
-  std::string str;
-  str.resize(len);
-
-  auto res = httpd_req_get_url_query_str(req, &str[0], len + 1);
-  if (res != ESP_OK) {
-    ESP_LOGW(TAG, "Can't get query for request: %s", esp_err_to_name(res));
-    return {};
-  }
-
-  return {str};
-}
-
 optional<std::string> query_key_value(const char *query_url, size_t query_len, const char *key) {
   if (query_url == nullptr || query_len == 0) {
     return {};
   }
 
-  // Use stack buffer for typical query strings, heap fallback for large ones
-  SmallBufferWithHeapFallback<256, char> val(query_len);
-
+  // Value can't exceed query_len. Use small stack buffer for typical values,
+  // heap fallback for long ones (e.g. base64 IR data) to limit stack usage
+  // since callers may also have stack buffers for the query string.
+  SmallBufferWithHeapFallback<128, char> val(query_len);
   if (httpd_query_key_value(query_url, key, val.get(), query_len) != ESP_OK) {
     return {};
   }
@@ -88,6 +67,18 @@ optional<std::string> query_key_value(const char *query_url, size_t query_len, c
   return {val.get()};
 }
 
+bool query_has_key(const char *query_url, size_t query_len, const char *key) {
+  if (query_url == nullptr || query_len == 0) {
+    return false;
+  }
+  // Minimal buffer — we only care if the key exists, not the value
+  char buf[1];
+  // httpd_query_key_value returns ESP_OK if found, ESP_ERR_HTTPD_RESULT_TRUNC if found
+  // but value truncated (expected with 1-byte buffer), or other errors for invalid input
+  auto err = httpd_query_key_value(query_url, key, buf, sizeof(buf));
+  return err == ESP_OK || err == ESP_ERR_HTTPD_RESULT_TRUNC;
+}
+
 // Helper function for case-insensitive string region comparison
 bool str_ncmp_ci(const char *s1, const char *s2, size_t n) {
   for (size_t i = 0; i < n; i++) {
diff --git a/esphome/components/web_server_idf/utils.h b/esphome/components/web_server_idf/utils.h
index 87635c0458..027a2f7b6c 100644
--- a/esphome/components/web_server_idf/utils.h
+++ b/esphome/components/web_server_idf/utils.h
@@ -13,11 +13,8 @@ size_t url_decode(char *str);
 
 bool request_has_header(httpd_req_t *req, const char *name);
 optional<std::string> request_get_header(httpd_req_t *req, const char *name);
-optional<std::string> request_get_url_query(httpd_req_t *req);
 optional<std::string> query_key_value(const char *query_url, size_t query_len, const char *key);
-inline optional<std::string> query_key_value(const std::string &query_url, const std::string &key) {
-  return query_key_value(query_url.c_str(), query_url.size(), key.c_str());
-}
+bool query_has_key(const char *query_url, size_t query_len, const char *key);
 
 // Helper function for case-insensitive character comparison
 inline bool char_equals_ci(char a, char b) { return ::tolower(a) == ::tolower(b); }
diff --git a/esphome/components/web_server_idf/web_server_idf.cpp b/esphome/components/web_server_idf/web_server_idf.cpp
index f1f89beb49..1798159e7f 100644
--- a/esphome/components/web_server_idf/web_server_idf.cpp
+++ b/esphome/components/web_server_idf/web_server_idf.cpp
@@ -393,13 +393,7 @@ AsyncWebParameter *AsyncWebServerRequest::getParam(const char *name) {
   }
 
   // Look up value from query strings
-  optional<std::string> val = query_key_value(this->post_query_.c_str(), this->post_query_.size(), name);
-  if (!val.has_value()) {
-    auto url_query = request_get_url_query(*this);
-    if (url_query.has_value()) {
-      val = query_key_value(url_query.value().c_str(), url_query.value().size(), name);
-    }
-  }
+  auto val = this->find_query_value_(name);
 
   // Don't cache misses to avoid wasting memory when handlers check for
   // optional parameters that don't exist in the request
@@ -412,6 +406,50 @@ AsyncWebParameter *AsyncWebServerRequest::getParam(const char *name) {
   return param;
 }
 
+/// Search post_query then URL query with a callback.
+/// Returns first truthy result, or value-initialized default.
+/// URL query is accessed directly from req->uri (same pattern as url_to()).
+template<typename Func>
+static auto search_query_sources(httpd_req_t *req, const std::string &post_query, const char *name, Func func)
+    -> decltype(func(nullptr, size_t{0}, name)) {
+  if (!post_query.empty()) {
+    auto result = func(post_query.c_str(), post_query.size(), name);
+    if (result) {
+      return result;
+    }
+  }
+  // Use httpd API for query length, then access string directly from URI.
+  // http_parser identifies components by offset/length without modifying the URI string.
+  // This is the same pattern used by url_to().
+  auto len = httpd_req_get_url_query_len(req);
+  if (len == 0) {
+    return {};
+  }
+  const char *query = strchr(req->uri, '?');
+  if (query == nullptr) {
+    return {};
+  }
+  query++;  // skip '?'
+  return func(query, len, name);
+}
+
+optional<std::string> AsyncWebServerRequest::find_query_value_(const char *name) const {
+  return search_query_sources(this->req_, this->post_query_, name,
+                              [](const char *q, size_t len, const char *k) { return query_key_value(q, len, k); });
+}
+
+bool AsyncWebServerRequest::hasArg(const char *name) {
+  return search_query_sources(this->req_, this->post_query_, name, query_has_key);
+}
+
+std::string AsyncWebServerRequest::arg(const char *name) {
+  auto val = this->find_query_value_(name);
+  if (val.has_value()) {
+    return std::move(val.value());
+  }
+  return {};
+}
+
 void AsyncWebServerResponse::addHeader(const char *name, const char *value) {
   httpd_resp_set_hdr(*this->req_, name, value);
 }
diff --git a/esphome/components/web_server_idf/web_server_idf.h b/esphome/components/web_server_idf/web_server_idf.h
index 6a409de74e..12df0303de 100644
--- a/esphome/components/web_server_idf/web_server_idf.h
+++ b/esphome/components/web_server_idf/web_server_idf.h
@@ -170,14 +170,8 @@ class AsyncWebServerRequest {
   AsyncWebParameter *getParam(const std::string &name) { return this->getParam(name.c_str()); }
 
   // NOLINTNEXTLINE(readability-identifier-naming)
-  bool hasArg(const char *name) { return this->hasParam(name); }
-  std::string arg(const char *name) {
-    auto *param = this->getParam(name);
-    if (param) {
-      return param->value();
-    }
-    return {};
-  }
+  bool hasArg(const char *name);
+  std::string arg(const char *name);
   std::string arg(const std::string &name) { return this->arg(name.c_str()); }
 
   operator httpd_req_t *() const { return this->req_; }
@@ -192,6 +186,7 @@ class AsyncWebServerRequest {
   // is faster than tree/hash overhead. AsyncWebParameter stores both name and value to avoid
   // duplicate storage. Only successful lookups are cached to prevent cache pollution when
   // handlers check for optional parameters that don't exist.
+  optional<std::string> find_query_value_(const char *name) const;
   std::vector<AsyncWebParameter *> params_;
   std::string post_query_;
   AsyncWebServerRequest(httpd_req_t *req) : req_(req) {}

From 0dcff82bb479b131a4dbb33d00940c7a91120dc2 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Thu, 12 Feb 2026 11:14:36 -0600
Subject: [PATCH 4/8] [wifi] Deprecate wifi_ssid() in favor of wifi_ssid_to()
 (#13958)

---
 esphome/components/wifi/wifi_component.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/esphome/components/wifi/wifi_component.h b/esphome/components/wifi/wifi_component.h
index ac28a1bc81..53ff0d9cad 100644
--- a/esphome/components/wifi/wifi_component.h
+++ b/esphome/components/wifi/wifi_component.h
@@ -502,6 +502,8 @@ class WiFiComponent : public Component {
   }
 
   network::IPAddresses wifi_sta_ip_addresses();
+  // Remove before 2026.9.0
+  ESPDEPRECATED("Use wifi_ssid_to() instead. Removed in 2026.9.0", "2026.3.0")
   std::string wifi_ssid();
   /// Write SSID to buffer without heap allocation.
   /// Returns pointer to buffer, or empty string if not connected.

From e3a457e40268949364f776fd5ec3ff5fd833a443 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Luk=C3=A1=C5=A1=20Ma=C5=88as?= <lukas.manas@gmail.com>
Date: Thu, 12 Feb 2026 18:20:54 +0100
Subject: [PATCH 5/8] [pulse_meter] Fix early edge detection (#12360)

Co-authored-by: pre-commit-ci-lite[bot] <117423508+pre-commit-ci-lite[bot]@users.noreply.github.com>
Co-authored-by: Jonathan Swoboda <154711427+swoboda1337@users.noreply.github.com>
---
 .../pulse_meter/pulse_meter_sensor.cpp        | 75 ++++++++++---------
 .../pulse_meter/pulse_meter_sensor.h          | 11 ++-
 2 files changed, 44 insertions(+), 42 deletions(-)

diff --git a/esphome/components/pulse_meter/pulse_meter_sensor.cpp b/esphome/components/pulse_meter/pulse_meter_sensor.cpp
index 007deb66e5..433e1f0b7e 100644
--- a/esphome/components/pulse_meter/pulse_meter_sensor.cpp
+++ b/esphome/components/pulse_meter/pulse_meter_sensor.cpp
@@ -38,8 +38,7 @@ void PulseMeterSensor::setup() {
 }
 
 void PulseMeterSensor::loop() {
-  // Reset the count in get before we pass it back to the ISR as set
-  this->get_->count_ = 0;
+  State state;
 
   {
     // Lock the interrupt so the interrupt code doesn't interfere with itself
@@ -58,31 +57,35 @@ void PulseMeterSensor::loop() {
     }
     this->last_pin_val_ = current;
 
-    // Swap out set and get to get the latest state from the ISR
-    std::swap(this->set_, this->get_);
+    // Get the latest state from the ISR and reset the count in the ISR
+    state.last_detected_edge_us_ = this->state_.last_detected_edge_us_;
+    state.last_rising_edge_us_ = this->state_.last_rising_edge_us_;
+    state.count_ = this->state_.count_;
+    this->state_.count_ = 0;
   }
 
   const uint32_t now = micros();
 
   // If an edge was peeked, repay the debt
-  if (this->peeked_edge_ && this->get_->count_ > 0) {
+  if (this->peeked_edge_ && state.count_ > 0) {
     this->peeked_edge_ = false;
-    this->get_->count_--;  // NOLINT(clang-diagnostic-deprecated-volatile)
+    state.count_--;
   }
 
-  // If there is an unprocessed edge, and filter_us_ has passed since, count this edge early
-  if (this->get_->last_rising_edge_us_ != this->get_->last_detected_edge_us_ &&
-      now - this->get_->last_rising_edge_us_ >= this->filter_us_) {
+  // If there is an unprocessed edge, and filter_us_ has passed since, count this edge early.
+  // Wait for the debt to be repaid before counting another unprocessed edge early.
+  if (!this->peeked_edge_ && state.last_rising_edge_us_ != state.last_detected_edge_us_ &&
+      now - state.last_rising_edge_us_ >= this->filter_us_) {
     this->peeked_edge_ = true;
-    this->get_->last_detected_edge_us_ = this->get_->last_rising_edge_us_;
-    this->get_->count_++;  // NOLINT(clang-diagnostic-deprecated-volatile)
+    state.last_detected_edge_us_ = state.last_rising_edge_us_;
+    state.count_++;
   }
 
   // Check if we detected a pulse this loop
-  if (this->get_->count_ > 0) {
+  if (state.count_ > 0) {
     // Keep a running total of pulses if a total sensor is configured
     if (this->total_sensor_ != nullptr) {
-      this->total_pulses_ += this->get_->count_;
+      this->total_pulses_ += state.count_;
       const uint32_t total = this->total_pulses_;
       this->total_sensor_->publish_state(total);
     }
@@ -94,15 +97,15 @@ void PulseMeterSensor::loop() {
         this->meter_state_ = MeterState::RUNNING;
       } break;
       case MeterState::RUNNING: {
-        uint32_t delta_us = this->get_->last_detected_edge_us_ - this->last_processed_edge_us_;
-        float pulse_width_us = delta_us / float(this->get_->count_);
-        ESP_LOGV(TAG, "New pulse, delta: %" PRIu32 " µs, count: %" PRIu32 ", width: %.5f µs", delta_us,
-                 this->get_->count_, pulse_width_us);
+        uint32_t delta_us = state.last_detected_edge_us_ - this->last_processed_edge_us_;
+        float pulse_width_us = delta_us / float(state.count_);
+        ESP_LOGV(TAG, "New pulse, delta: %" PRIu32 " µs, count: %" PRIu32 ", width: %.5f µs", delta_us, state.count_,
+                 pulse_width_us);
         this->publish_state((60.0f * 1000000.0f) / pulse_width_us);
       } break;
     }
 
-    this->last_processed_edge_us_ = this->get_->last_detected_edge_us_;
+    this->last_processed_edge_us_ = state.last_detected_edge_us_;
   }
   // No detected edges this loop
   else {
@@ -141,14 +144,14 @@ void IRAM_ATTR PulseMeterSensor::edge_intr(PulseMeterSensor *sensor) {
   // This is an interrupt handler - we can't call any virtual method from this method
   // Get the current time before we do anything else so the measurements are consistent
   const uint32_t now = micros();
-  auto &state = sensor->edge_state_;
-  auto &set = *sensor->set_;
+  auto &edge_state = sensor->edge_state_;
+  auto &state = sensor->state_;
 
-  if ((now - state.last_sent_edge_us_) >= sensor->filter_us_) {
-    state.last_sent_edge_us_ = now;
-    set.last_detected_edge_us_ = now;
-    set.last_rising_edge_us_ = now;
-    set.count_++;  // NOLINT(clang-diagnostic-deprecated-volatile)
+  if ((now - edge_state.last_sent_edge_us_) >= sensor->filter_us_) {
+    edge_state.last_sent_edge_us_ = now;
+    state.last_detected_edge_us_ = now;
+    state.last_rising_edge_us_ = now;
+    state.count_++;  // NOLINT(clang-diagnostic-deprecated-volatile)
   }
 
   // This ISR is bound to rising edges, so the pin is high
@@ -160,26 +163,26 @@ void IRAM_ATTR PulseMeterSensor::pulse_intr(PulseMeterSensor *sensor) {
   // Get the current time before we do anything else so the measurements are consistent
   const uint32_t now = micros();
   const bool pin_val = sensor->isr_pin_.digital_read();
-  auto &state = sensor->pulse_state_;
-  auto &set = *sensor->set_;
+  auto &pulse_state = sensor->pulse_state_;
+  auto &state = sensor->state_;
 
   // Filter length has passed since the last interrupt
-  const bool length = now - state.last_intr_ >= sensor->filter_us_;
+  const bool length = now - pulse_state.last_intr_ >= sensor->filter_us_;
 
-  if (length && state.latched_ && !sensor->last_pin_val_) {  // Long enough low edge
-    state.latched_ = false;
-  } else if (length && !state.latched_ && sensor->last_pin_val_) {  // Long enough high edge
-    state.latched_ = true;
-    set.last_detected_edge_us_ = state.last_intr_;
-    set.count_++;  // NOLINT(clang-diagnostic-deprecated-volatile)
+  if (length && pulse_state.latched_ && !sensor->last_pin_val_) {  // Long enough low edge
+    pulse_state.latched_ = false;
+  } else if (length && !pulse_state.latched_ && sensor->last_pin_val_) {  // Long enough high edge
+    pulse_state.latched_ = true;
+    state.last_detected_edge_us_ = pulse_state.last_intr_;
+    state.count_++;  // NOLINT(clang-diagnostic-deprecated-volatile)
   }
 
   // Due to order of operations this includes
   //    length && latched && rising   (just reset from a long low edge)
   //    !latched && (rising || high)  (noise on the line resetting the potential rising edge)
-  set.last_rising_edge_us_ = !state.latched_ && pin_val ? now : set.last_detected_edge_us_;
+  state.last_rising_edge_us_ = !pulse_state.latched_ && pin_val ? now : state.last_detected_edge_us_;
 
-  state.last_intr_ = now;
+  pulse_state.last_intr_ = now;
   sensor->last_pin_val_ = pin_val;
 }
 
diff --git a/esphome/components/pulse_meter/pulse_meter_sensor.h b/esphome/components/pulse_meter/pulse_meter_sensor.h
index 5800c4ec42..e46f1e615f 100644
--- a/esphome/components/pulse_meter/pulse_meter_sensor.h
+++ b/esphome/components/pulse_meter/pulse_meter_sensor.h
@@ -46,17 +46,16 @@ class PulseMeterSensor : public sensor::Sensor, public Component {
   uint32_t total_pulses_ = 0;
   uint32_t last_processed_edge_us_ = 0;
 
-  // This struct (and the two pointers) are used to pass data between the ISR and loop.
-  // These two pointers are exchanged each loop.
-  // Use these to send data from the ISR to the loop not the other way around (except for resetting the values).
+  // This struct and variable are used to pass data between the ISR and loop.
+  // The data from state_ is read and then count_ in state_ is reset in each loop.
+  // This must be done while guarded by an InterruptLock. Use this variable to send data
+  // from the ISR to the loop not the other way around (except for resetting count_).
   struct State {
     uint32_t last_detected_edge_us_ = 0;
     uint32_t last_rising_edge_us_ = 0;
     uint32_t count_ = 0;
   };
-  State state_[2];
-  volatile State *set_ = state_;
-  volatile State *get_ = state_ + 1;
+  volatile State state_{};
 
   // Only use the following variables in the ISR or while guarded by an InterruptLock
   ISRInternalGPIOPin isr_pin_;

From 7fd535179e4cc793047ebcf802b0fe174b3987cb Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Thu, 12 Feb 2026 11:47:44 -0600
Subject: [PATCH 6/8] [helpers] Add heap warnings to format_hex_pretty,
 deprecate ethernet/web_server std::string APIs (#13959)

---
 .../components/ethernet/ethernet_component.h   |  2 ++
 .../components/web_server_idf/web_server_idf.h |  3 ++-
 esphome/core/helpers.h                         | 18 ++++++++++++++++++
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/esphome/components/ethernet/ethernet_component.h b/esphome/components/ethernet/ethernet_component.h
index 5a2869c5a7..b4859c308d 100644
--- a/esphome/components/ethernet/ethernet_component.h
+++ b/esphome/components/ethernet/ethernet_component.h
@@ -110,6 +110,8 @@ class EthernetComponent : public Component {
   const char *get_use_address() const;
   void set_use_address(const char *use_address);
   void get_eth_mac_address_raw(uint8_t *mac);
+  // Remove before 2026.9.0
+  ESPDEPRECATED("Use get_eth_mac_address_pretty_into_buffer() instead. Removed in 2026.9.0", "2026.3.0")
   std::string get_eth_mac_address_pretty();
   const char *get_eth_mac_address_pretty_into_buffer(std::span<char, MAC_ADDRESS_PRETTY_BUFFER_SIZE> buf);
   eth_duplex_t get_duplex_mode();
diff --git a/esphome/components/web_server_idf/web_server_idf.h b/esphome/components/web_server_idf/web_server_idf.h
index 12df0303de..74601ffda8 100644
--- a/esphome/components/web_server_idf/web_server_idf.h
+++ b/esphome/components/web_server_idf/web_server_idf.h
@@ -116,7 +116,8 @@ class AsyncWebServerRequest {
   /// Write URL (without query string) to buffer, returns StringRef pointing to buffer.
   /// URL is decoded (e.g., %20 -> space).
   StringRef url_to(std::span<char, URL_BUF_SIZE> buffer) const;
-  /// Get URL as std::string. Prefer url_to() to avoid heap allocation.
+  // Remove before 2026.9.0
+  ESPDEPRECATED("Use url_to() instead. Removed in 2026.9.0", "2026.3.0")
   std::string url() const {
     char buffer[URL_BUF_SIZE];
     return std::string(this->url_to(buffer));
diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index f7de34b6d5..34c7452484 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -1083,6 +1083,9 @@ template<std::size_t N> std::string format_hex(const std::array<uint8_t, N> &dat
  * Each byte is displayed as a two-digit uppercase hex value, separated by the specified separator.
  * Optionally includes the total byte count in parentheses at the end.
  *
+ * @warning Allocates heap memory. Use format_hex_pretty_to() with a stack buffer instead.
+ * Causes heap fragmentation on long-running devices.
+ *
  * @param data Pointer to the byte array to format.
  * @param length Number of bytes in the array.
  * @param separator Character to use between hex bytes (default: '.').
@@ -1108,6 +1111,9 @@ std::string format_hex_pretty(const uint8_t *data, size_t length, char separator
  *
  * Similar to the byte array version, but formats 16-bit words as 4-digit hex values.
  *
+ * @warning Allocates heap memory. Use format_hex_pretty_to() with a stack buffer instead.
+ * Causes heap fragmentation on long-running devices.
+ *
  * @param data Pointer to the 16-bit word array to format.
  * @param length Number of 16-bit words in the array.
  * @param separator Character to use between hex words (default: '.').
@@ -1131,6 +1137,9 @@ std::string format_hex_pretty(const uint16_t *data, size_t length, char separato
  * Convenience overload for std::vector<uint8_t>. Formats each byte as a two-digit
  * uppercase hex value with customizable separator.
  *
+ * @warning Allocates heap memory. Use format_hex_pretty_to() with a stack buffer instead.
+ * Causes heap fragmentation on long-running devices.
+ *
  * @param data Vector of bytes to format.
  * @param separator Character to use between hex bytes (default: '.').
  * @param show_length Whether to append the byte count in parentheses (default: true).
@@ -1154,6 +1163,9 @@ std::string format_hex_pretty(const std::vector<uint8_t> &data, char separator =
  * Convenience overload for std::vector<uint16_t>. Each 16-bit word is formatted
  * as a 4-digit uppercase hex value in big-endian order.
  *
+ * @warning Allocates heap memory. Use format_hex_pretty_to() with a stack buffer instead.
+ * Causes heap fragmentation on long-running devices.
+ *
  * @param data Vector of 16-bit words to format.
  * @param separator Character to use between hex words (default: '.').
  * @param show_length Whether to append the word count in parentheses (default: true).
@@ -1176,6 +1188,9 @@ std::string format_hex_pretty(const std::vector<uint16_t> &data, char separator
  * Treats each character in the string as a byte and formats it in hex.
  * Useful for debugging binary data stored in std::string containers.
  *
+ * @warning Allocates heap memory. Use format_hex_pretty_to() with a stack buffer instead.
+ * Causes heap fragmentation on long-running devices.
+ *
  * @param data String whose bytes should be formatted as hex.
  * @param separator Character to use between hex bytes (default: '.').
  * @param show_length Whether to append the byte count in parentheses (default: true).
@@ -1198,6 +1213,9 @@ std::string format_hex_pretty(const std::string &data, char separator = '.', boo
  * Converts the integer to big-endian byte order and formats each byte as hex.
  * The most significant byte appears first in the output string.
  *
+ * @warning Allocates heap memory. Use format_hex_pretty_to() with a stack buffer instead.
+ * Causes heap fragmentation on long-running devices.
+ *
  * @tparam T Unsigned integer type (uint8_t, uint16_t, uint32_t, uint64_t, etc.).
  * @param val The unsigned integer value to format.
  * @param separator Character to use between hex bytes (default: '.').

From 58f80292642dc5a4e23fde673ed06c7b8ebc5fcb Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Thu, 12 Feb 2026 12:21:52 -0600
Subject: [PATCH 7/8] [wifi] Use memcpy-based insertion sort for scan results

Replace copy-assignment with raw memcpy in the WiFi scan result
insertion sort. Copy assignment on WiFiScanResult calls
CompactString's destructor then placement-new for every shift,
which means delete[]/new[] per shift for heap-allocated SSIDs.

With 70+ networks visible (e.g., during captive portal transition
showing full scan results), this caused event loop blocking from
hundreds of heap allocations in a tight loop on an 80MHz ESP8266.

This optimization is safe because we're permuting elements within
the same array - each slot is overwritten exactly once, so no
ownership duplication occurs. CompactString stores either inline
data or a heap pointer, never a self-referential pointer (unlike
libstdc++ std::string SSO). This was made possible by PR#13472
which replaced std::string with CompactString.

Static asserts guard the memcpy safety assumptions at compile time.

Confirmed on real device: event loop blocking during captive portal
transition is eliminated and WiFi connection is slightly faster.
---
 esphome/components/wifi/wifi_component.cpp | 46 ++++++++++++++++++++--
 esphome/components/wifi/wifi_component.h   |  6 +++
 2 files changed, 48 insertions(+), 4 deletions(-)

diff --git a/esphome/components/wifi/wifi_component.cpp b/esphome/components/wifi/wifi_component.cpp
index 61d05d7635..99c8b5f228 100644
--- a/esphome/components/wifi/wifi_component.cpp
+++ b/esphome/components/wifi/wifi_component.cpp
@@ -1319,20 +1319,58 @@ void WiFiComponent::start_scanning() {
 // Using insertion sort instead of std::stable_sort saves flash memory
 // by avoiding template instantiations (std::rotate, std::stable_sort, lambdas)
 // IMPORTANT: This sort is stable (preserves relative order of equal elements)
+//
+// Uses raw memcpy instead of copy assignment to avoid CompactString's
+// destructor/constructor overhead (heap delete[]/new[] for long SSIDs).
+// Copy assignment calls ~CompactString() then placement-new for every shift,
+// which means delete[]/new[] per shift for heap-allocated SSIDs. With 70+
+// networks (e.g., captive portal showing full scan results), this caused
+// event loop blocking from hundreds of heap operations in a tight loop.
+//
+// This is safe because we're permuting elements within the same array —
+// each slot is overwritten exactly once, so no ownership duplication occurs.
+// All members of WiFiScanResult are either trivially copyable (bssid, channel,
+// rssi, priority, flags) or CompactString, which stores either inline data or
+// a heap pointer — never a self-referential pointer (unlike std::string's SSO
+// on some implementations). This was not possible before PR#13472 replaced
+// std::string with CompactString, since std::string's internal layout is
+// implementation-defined and may use self-referential pointers.
 template<typename VectorType> static void insertion_sort_scan_results(VectorType &results) {
+  // memcpy-based sort requires no self-referential pointers or virtual dispatch.
+  // These static_asserts guard the assumptions. If any fire, the memcpy sort
+  // must be reviewed for safety before updating the expected values.
+  //
+  // No vtable pointers (memcpy would corrupt vptr)
+  static_assert(!std::is_polymorphic<WiFiScanResult>::value, "WiFiScanResult must not have vtable");
+  static_assert(!std::is_polymorphic<CompactString>::value, "CompactString must not have vtable");
+  // Standard layout ensures predictable memory layout with no virtual bases
+  // and no mixed-access-specifier reordering
+  static_assert(std::is_standard_layout<WiFiScanResult>::value, "WiFiScanResult must be standard layout");
+  static_assert(std::is_standard_layout<CompactString>::value, "CompactString must be standard layout");
+  // Size checks catch added/removed fields that may need safety review
+  static_assert(sizeof(WiFiScanResult) == 32, "WiFiScanResult size changed - verify memcpy sort is still safe");
+  static_assert(sizeof(CompactString) == 20, "CompactString size changed - verify memcpy sort is still safe");
+  // Alignment must match for reinterpret_cast of key_buf to be valid
+  static_assert(alignof(WiFiScanResult) <= alignof(std::max_align_t), "WiFiScanResult alignment exceeds max_align_t");
   const size_t size = results.size();
+  constexpr size_t elem_size = sizeof(WiFiScanResult);
+  // Suppress warnings for intentional memcpy on non-trivially-copyable type.
+  // Safety is guaranteed by the static_asserts above and the permutation invariant.
+  // NOLINTNEXTLINE(bugprone-undefined-memory-manipulation)
+  auto *memcpy_fn = &memcpy;
   for (size_t i = 1; i < size; i++) {
-    // Make a copy to avoid issues with move semantics during comparison
-    WiFiScanResult key = results[i];
+    alignas(WiFiScanResult) uint8_t key_buf[elem_size];
+    memcpy_fn(key_buf, &results[i], elem_size);
+    const auto &key = *reinterpret_cast<const WiFiScanResult *>(key_buf);
     int32_t j = i - 1;
 
     // Move elements that are worse than key to the right
     // For stability, we only move if key is strictly better than results[j]
     while (j >= 0 && wifi_scan_result_is_better(key, results[j])) {
-      results[j + 1] = results[j];
+      memcpy_fn(&results[j + 1], &results[j], elem_size);
       j--;
     }
-    results[j + 1] = key;
+    memcpy_fn(&results[j + 1], key_buf, elem_size);
   }
 }
 
diff --git a/esphome/components/wifi/wifi_component.h b/esphome/components/wifi/wifi_component.h
index 53ff0d9cad..f0ccc95abe 100644
--- a/esphome/components/wifi/wifi_component.h
+++ b/esphome/components/wifi/wifi_component.h
@@ -219,6 +219,12 @@ class CompactString {
 };
 
 static_assert(sizeof(CompactString) == 20, "CompactString must be exactly 20 bytes");
+// CompactString is safe to memcpy for permutation-based sorting (no ownership duplication).
+// Unlike libstdc++ std::string which uses a self-referential pointer (_M_p -> _M_local_buf)
+// in SSO mode, CompactString stores either inline data or an external heap pointer in
+// storage_[] — never a pointer to itself. These asserts guard that property.
+static_assert(std::is_standard_layout<CompactString>::value, "CompactString must be standard layout for memcpy safety");
+static_assert(!std::is_polymorphic<CompactString>::value, "CompactString must not have vtable for memcpy safety");
 
 class WiFiAP {
   friend class WiFiComponent;

From 282ba90f6281140fd8a13cf7e20af219cdf4cf06 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Thu, 12 Feb 2026 12:32:06 -0600
Subject: [PATCH 8/8] Address review feedback: add explicit includes and
 clarify comments

- Add #include <type_traits> to both .cpp and .h for static_asserts
- Clarify CompactString comment: explicitly note it is not trivially
  copyable, and that memcpy safety relies on validated layout property
- Use memcpy_fn indirection to suppress both GCC -Wclass-memaccess
  and clang-tidy bugprone-undefined-memory-manipulation without
  platform-specific pragma guards
---
 esphome/components/wifi/wifi_component.cpp |  1 +
 esphome/components/wifi/wifi_component.h   | 15 +++++++++------
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/esphome/components/wifi/wifi_component.cpp b/esphome/components/wifi/wifi_component.cpp
index 99c8b5f228..52188b2621 100644
--- a/esphome/components/wifi/wifi_component.cpp
+++ b/esphome/components/wifi/wifi_component.cpp
@@ -3,6 +3,7 @@
 #include <cassert>
 #include <cinttypes>
 #include <cmath>
+#include <type_traits>
 
 #ifdef USE_ESP32
 #if (ESP_IDF_VERSION_MAJOR >= 5 && ESP_IDF_VERSION_MINOR >= 1)
diff --git a/esphome/components/wifi/wifi_component.h b/esphome/components/wifi/wifi_component.h
index f0ccc95abe..7ae8a2c18a 100644
--- a/esphome/components/wifi/wifi_component.h
+++ b/esphome/components/wifi/wifi_component.h
@@ -10,6 +10,7 @@
 
 #include <span>
 #include <string>
+#include <type_traits>
 #include <vector>
 
 #ifdef USE_LIBRETINY
@@ -219,12 +220,14 @@ class CompactString {
 };
 
 static_assert(sizeof(CompactString) == 20, "CompactString must be exactly 20 bytes");
-// CompactString is safe to memcpy for permutation-based sorting (no ownership duplication).
-// Unlike libstdc++ std::string which uses a self-referential pointer (_M_p -> _M_local_buf)
-// in SSO mode, CompactString stores either inline data or an external heap pointer in
-// storage_[] — never a pointer to itself. These asserts guard that property.
-static_assert(std::is_standard_layout<CompactString>::value, "CompactString must be standard layout for memcpy safety");
-static_assert(!std::is_polymorphic<CompactString>::value, "CompactString must not have vtable for memcpy safety");
+// CompactString is not trivially copyable (non-trivial destructor/copy for heap case).
+// However, its layout has no self-referential pointers: storage_[] contains either inline
+// data or an external heap pointer — never a pointer to itself. This is unlike libstdc++
+// std::string SSO where _M_p points to _M_local_buf within the same object.
+// This property allows memcpy-based permutation sorting where each element ends up in
+// exactly one slot (no ownership duplication). These asserts document that layout property.
+static_assert(std::is_standard_layout<CompactString>::value, "CompactString must be standard layout");
+static_assert(!std::is_polymorphic<CompactString>::value, "CompactString must not have vtable");
 
 class WiFiAP {
   friend class WiFiComponent;