diff --git a/esphome/components/api/__init__.py b/esphome/components/api/__init__.py
index 918f56349aa..dd99862cc27 100644
--- a/esphome/components/api/__init__.py
+++ b/esphome/components/api/__init__.py
@@ -541,17 +541,24 @@ async def homeassistant_service_to_code(
     # Initialize FixedVectors with exact sizes from config
     cg.add(var.init_data(len(config[CONF_DATA])))
     for key, value in config[CONF_DATA].items():
-        templ = await cg.templatable(value, args, cg.std_string)
+        # output_type=None because lambdas can return non-string types (int,
+        # float, char*) that TemplatableStringValue converts via to_string.
+        # Static strings are manually wrapped for PROGMEM on ESP8266.
+        templ = await cg.templatable(value, args, None)
+        if isinstance(templ, str):
+            templ = cg.FlashStringLiteral(templ)
         cg.add(var.add_data(cg.FlashStringLiteral(key), templ))
 
     cg.add(var.init_data_template(len(config[CONF_DATA_TEMPLATE])))
     for key, value in config[CONF_DATA_TEMPLATE].items():
-        templ = await cg.templatable(value, args, cg.std_string)
+        templ = await cg.templatable(value, args, None)
+        if isinstance(templ, str):
+            templ = cg.FlashStringLiteral(templ)
         cg.add(var.add_data_template(cg.FlashStringLiteral(key), templ))
 
     cg.add(var.init_variables(len(config[CONF_VARIABLES])))
     for key, value in config[CONF_VARIABLES].items():
-        templ = await cg.templatable(value, args, cg.std_string)
+        templ = await cg.templatable(value, args, None)
         cg.add(var.add_variable(cg.FlashStringLiteral(key), templ))
 
     if on_error := config.get(CONF_ON_ERROR):
@@ -627,17 +634,24 @@ async def homeassistant_event_to_code(config, action_id, template_arg, args):
     # Initialize FixedVectors with exact sizes from config
     cg.add(var.init_data(len(config[CONF_DATA])))
     for key, value in config[CONF_DATA].items():
-        templ = await cg.templatable(value, args, cg.std_string)
+        # output_type=None because lambdas can return non-string types (int,
+        # float, char*) that TemplatableStringValue converts via to_string.
+        # Static strings are manually wrapped for PROGMEM on ESP8266.
+        templ = await cg.templatable(value, args, None)
+        if isinstance(templ, str):
+            templ = cg.FlashStringLiteral(templ)
         cg.add(var.add_data(cg.FlashStringLiteral(key), templ))
 
     cg.add(var.init_data_template(len(config[CONF_DATA_TEMPLATE])))
     for key, value in config[CONF_DATA_TEMPLATE].items():
-        templ = await cg.templatable(value, args, cg.std_string)
+        templ = await cg.templatable(value, args, None)
+        if isinstance(templ, str):
+            templ = cg.FlashStringLiteral(templ)
         cg.add(var.add_data_template(cg.FlashStringLiteral(key), templ))
 
     cg.add(var.init_variables(len(config[CONF_VARIABLES])))
     for key, value in config[CONF_VARIABLES].items():
-        templ = await cg.templatable(value, args, cg.std_string)
+        templ = await cg.templatable(value, args, None)
         cg.add(var.add_variable(cg.FlashStringLiteral(key), templ))
 
     return var
diff --git a/esphome/components/api/homeassistant_service.h b/esphome/components/api/homeassistant_service.h
index 677d0645d62..9d14061d072 100644
--- a/esphome/components/api/homeassistant_service.h
+++ b/esphome/components/api/homeassistant_service.h
@@ -236,10 +236,11 @@ template<typename... Ts> class HomeAssistantServiceCallAction : public Action<Ts
     dest.init(source.size());
 
 #ifdef USE_ESP8266
-    // On ESP8266, keys may be in PROGMEM (from ESPHOME_F in codegen) and
-    // FLASH_STRING values need copying via _P functions.
-    // Allocate storage for all keys + all values (2 entries per source item).
-    // strlen_P/memcpy_P handle both RAM and PROGMEM pointers safely.
+    // On ESP8266, all static strings from codegen are FLASH_STRING (PROGMEM),
+    // so is_static_string() is always false — the zero-copy STATIC_STRING fast
+    // path from the non-ESP8266 branch cannot trigger. We copy all keys and
+    // values unconditionally: keys via _P functions (may be in PROGMEM), values
+    // via value() which handles FLASH_STRING internally.
     value_storage.init(source.size() * 2);
 
     for (auto &it : source) {
diff --git a/esphome/cpp_generator.py b/esphome/cpp_generator.py
index e1f76a2cca8..5457485d254 100644
--- a/esphome/cpp_generator.py
+++ b/esphome/cpp_generator.py
@@ -780,8 +780,13 @@ async def templatable(
     if to_exp is None:
         # Automatically wrap static strings in ESPHOME_F() for PROGMEM storage on ESP8266.
         # On other platforms ESPHOME_F() is a no-op returning const char*.
-        if isinstance(value, str) and str(output_type) == "std::string":
-            return FlashStringLiteral(value)
+        # Lazy import to avoid circular dependency (cpp_generator <-> cpp_types).
+        # Identity check (is) avoids brittle string comparison.
+        if isinstance(value, str) and output_type is not None:
+            from esphome.cpp_types import std_string
+
+            if output_type is std_string:
+                return FlashStringLiteral(value)
         return value
     if isinstance(to_exp, dict):
         return to_exp[value]