[api] Emit raw tag+value writes for force=true fixed32 fields

Instead of ALWAYS_INLINE on encode_field_raw (which bloated all
callers), have the code generator precompute the tag byte and emit
write_raw_byte(tag) + write_fixed32_raw(value) directly.

This gives the same tight codegen (single byte store + memcpy) for
key fields without inflating encode_bool/encode_uint32/etc.

+108 bytes flash vs baseline, -48 bytes vs the ALWAYS_INLINE approach.

esphome/components/api/api_pb2.cpp

@@ -208,7 +208,8 @@ uint32_t DeviceInfoResponse::calculate_size() const {
 #ifdef USE_BINARY_SENSOR
 void ListEntitiesBinarySensorResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
   buffer.encode_string(5, this->device_class);
   buffer.encode_bool(6, this->is_status_binary_sensor);
@@ -239,7 +240,8 @@ uint32_t ListEntitiesBinarySensorResponse::calculate_size() const {
   return size;
 }
 void BinarySensorStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_bool(2, this->state);
   buffer.encode_bool(3, this->missing_state);
 #ifdef USE_DEVICES
@@ -260,7 +262,8 @@ uint32_t BinarySensorStateResponse::calculate_size() const {
 #ifdef USE_COVER
 void ListEntitiesCoverResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
   buffer.encode_bool(5, this->assumed_state);
   buffer.encode_bool(6, this->supports_position);
@@ -297,7 +300,8 @@ uint32_t ListEntitiesCoverResponse::calculate_size() const {
   return size;
 }
 void CoverStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_float(3, this->position);
   buffer.encode_float(4, this->tilt);
   buffer.encode_uint32(5, static_cast<uint32_t>(this->current_operation));
@@ -357,7 +361,8 @@ bool CoverCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #ifdef USE_FAN
 void ListEntitiesFanResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
   buffer.encode_bool(5, this->supports_oscillation);
   buffer.encode_bool(6, this->supports_speed);
@@ -400,7 +405,8 @@ uint32_t ListEntitiesFanResponse::calculate_size() const {
   return size;
 }
 void FanStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_bool(2, this->state);
   buffer.encode_bool(3, this->oscillating);
   buffer.encode_uint32(5, static_cast<uint32_t>(this->direction));
@@ -487,7 +493,8 @@ bool FanCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #ifdef USE_LIGHT
 void ListEntitiesLightResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
   for (const auto &it : *this->supported_color_modes) {
     buffer.encode_uint32(12, static_cast<uint32_t>(it), true);
@@ -534,7 +541,8 @@ uint32_t ListEntitiesLightResponse::calculate_size() const {
   return size;
 }
 void LightStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_bool(2, this->state);
   buffer.encode_float(3, this->brightness);
   buffer.encode_uint32(11, static_cast<uint32_t>(this->color_mode));
@@ -683,7 +691,8 @@ bool LightCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #ifdef USE_SENSOR
 void ListEntitiesSensorResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -720,7 +729,8 @@ uint32_t ListEntitiesSensorResponse::calculate_size() const {
   return size;
 }
 void SensorStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_float(2, this->state);
   buffer.encode_bool(3, this->missing_state);
 #ifdef USE_DEVICES
@@ -741,7 +751,8 @@ uint32_t SensorStateResponse::calculate_size() const {
 #ifdef USE_SWITCH
 void ListEntitiesSwitchResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -772,7 +783,8 @@ uint32_t ListEntitiesSwitchResponse::calculate_size() const {
   return size;
 }
 void SwitchStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_bool(2, this->state);
 #ifdef USE_DEVICES
   buffer.encode_uint32(3, this->device_id);
@@ -816,7 +828,8 @@ bool SwitchCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #ifdef USE_TEXT_SENSOR
 void ListEntitiesTextSensorResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -845,7 +858,8 @@ uint32_t ListEntitiesTextSensorResponse::calculate_size() const {
   return size;
 }
 void TextSensorStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(2, this->state);
   buffer.encode_bool(3, this->missing_state);
 #ifdef USE_DEVICES
@@ -1124,7 +1138,8 @@ uint32_t ListEntitiesServicesArgument::calculate_size() const {
 }
 void ListEntitiesServicesResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->name);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   for (auto &it : this->args) {
     buffer.encode_sub_message(3, it);
   }
@@ -1269,7 +1284,8 @@ uint32_t ExecuteServiceResponse::calculate_size() const {
 #ifdef USE_CAMERA
 void ListEntitiesCameraResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
   buffer.encode_bool(5, this->disabled_by_default);
 #ifdef USE_ENTITY_ICON
@@ -1296,7 +1312,8 @@ uint32_t ListEntitiesCameraResponse::calculate_size() const {
   return size;
 }
 void CameraImageResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_bytes(2, this->data_ptr_, this->data_len_);
   buffer.encode_bool(3, this->done);
 #ifdef USE_DEVICES
@@ -1330,7 +1347,8 @@ bool CameraImageRequest::decode_varint(uint32_t field_id, proto_varint_value_t v
 #ifdef USE_CLIMATE
 void ListEntitiesClimateResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
   buffer.encode_bool(5, this->supports_current_temperature);
   buffer.encode_bool(6, this->supports_two_point_target_temperature);
@@ -1429,7 +1447,8 @@ uint32_t ListEntitiesClimateResponse::calculate_size() const {
   return size;
 }
 void ClimateStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_uint32(2, static_cast<uint32_t>(this->mode));
   buffer.encode_float(3, this->current_temperature);
   buffer.encode_float(4, this->target_temperature);
@@ -1563,7 +1582,8 @@ bool ClimateCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #ifdef USE_WATER_HEATER
 void ListEntitiesWaterHeaterResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(4, this->icon);
@@ -1606,7 +1626,8 @@ uint32_t ListEntitiesWaterHeaterResponse::calculate_size() const {
   return size;
 }
 void WaterHeaterStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_float(2, this->current_temperature);
   buffer.encode_float(3, this->target_temperature);
   buffer.encode_uint32(4, static_cast<uint32_t>(this->mode));
@@ -1675,7 +1696,8 @@ bool WaterHeaterCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value
 #ifdef USE_NUMBER
 void ListEntitiesNumberResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -1714,7 +1736,8 @@ uint32_t ListEntitiesNumberResponse::calculate_size() const {
   return size;
 }
 void NumberStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_float(2, this->state);
   buffer.encode_bool(3, this->missing_state);
 #ifdef USE_DEVICES
@@ -1760,7 +1783,8 @@ bool NumberCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #ifdef USE_SELECT
 void ListEntitiesSelectResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -1795,7 +1819,8 @@ uint32_t ListEntitiesSelectResponse::calculate_size() const {
   return size;
 }
 void SelectStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(2, this->state);
   buffer.encode_bool(3, this->missing_state);
 #ifdef USE_DEVICES
@@ -1849,7 +1874,8 @@ bool SelectCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #ifdef USE_SIREN
 void ListEntitiesSirenResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -1888,7 +1914,8 @@ uint32_t ListEntitiesSirenResponse::calculate_size() const {
   return size;
 }
 void SirenStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_bool(2, this->state);
 #ifdef USE_DEVICES
   buffer.encode_uint32(3, this->device_id);
@@ -1961,7 +1988,8 @@ bool SirenCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #ifdef USE_LOCK
 void ListEntitiesLockResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -1996,7 +2024,8 @@ uint32_t ListEntitiesLockResponse::calculate_size() const {
   return size;
 }
 void LockStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_uint32(2, static_cast<uint32_t>(this->state));
 #ifdef USE_DEVICES
   buffer.encode_uint32(3, this->device_id);
@@ -2054,7 +2083,8 @@ bool LockCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #ifdef USE_BUTTON
 void ListEntitiesButtonResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -2124,7 +2154,8 @@ uint32_t MediaPlayerSupportedFormat::calculate_size() const {
 }
 void ListEntitiesMediaPlayerResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -2163,7 +2194,8 @@ uint32_t ListEntitiesMediaPlayerResponse::calculate_size() const {
   return size;
 }
 void MediaPlayerStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_uint32(2, static_cast<uint32_t>(this->state));
   buffer.encode_float(3, this->volume);
   buffer.encode_bool(4, this->muted);
@@ -2942,7 +2974,8 @@ bool VoiceAssistantSetConfiguration::decode_length(uint32_t field_id, ProtoLengt
 #ifdef USE_ALARM_CONTROL_PANEL
 void ListEntitiesAlarmControlPanelResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -2975,7 +3008,8 @@ uint32_t ListEntitiesAlarmControlPanelResponse::calculate_size() const {
   return size;
 }
 void AlarmControlPanelStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_uint32(2, static_cast<uint32_t>(this->state));
 #ifdef USE_DEVICES
   buffer.encode_uint32(3, this->device_id);
@@ -3030,7 +3064,8 @@ bool AlarmControlPanelCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit
 #ifdef USE_TEXT
 void ListEntitiesTextResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -3065,7 +3100,8 @@ uint32_t ListEntitiesTextResponse::calculate_size() const {
   return size;
 }
 void TextStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(2, this->state);
   buffer.encode_bool(3, this->missing_state);
 #ifdef USE_DEVICES
@@ -3119,7 +3155,8 @@ bool TextCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #ifdef USE_DATETIME_DATE
 void ListEntitiesDateResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -3146,7 +3183,8 @@ uint32_t ListEntitiesDateResponse::calculate_size() const {
   return size;
 }
 void DateStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_bool(2, this->missing_state);
   buffer.encode_uint32(3, this->year);
   buffer.encode_uint32(4, this->month);
@@ -3202,7 +3240,8 @@ bool DateCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #ifdef USE_DATETIME_TIME
 void ListEntitiesTimeResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -3229,7 +3268,8 @@ uint32_t ListEntitiesTimeResponse::calculate_size() const {
   return size;
 }
 void TimeStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_bool(2, this->missing_state);
   buffer.encode_uint32(3, this->hour);
   buffer.encode_uint32(4, this->minute);
@@ -3285,7 +3325,8 @@ bool TimeCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #ifdef USE_EVENT
 void ListEntitiesEventResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -3322,7 +3363,8 @@ uint32_t ListEntitiesEventResponse::calculate_size() const {
   return size;
 }
 void EventResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(2, this->event_type);
 #ifdef USE_DEVICES
   buffer.encode_uint32(3, this->device_id);
@@ -3341,7 +3383,8 @@ uint32_t EventResponse::calculate_size() const {
 #ifdef USE_VALVE
 void ListEntitiesValveResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -3376,7 +3419,8 @@ uint32_t ListEntitiesValveResponse::calculate_size() const {
   return size;
 }
 void ValveStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_float(2, this->position);
   buffer.encode_uint32(3, static_cast<uint32_t>(this->current_operation));
 #ifdef USE_DEVICES
@@ -3428,7 +3472,8 @@ bool ValveCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #ifdef USE_DATETIME_DATETIME
 void ListEntitiesDateTimeResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -3455,7 +3500,8 @@ uint32_t ListEntitiesDateTimeResponse::calculate_size() const {
   return size;
 }
 void DateTimeStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_bool(2, this->missing_state);
   buffer.encode_fixed32(3, this->epoch_seconds);
 #ifdef USE_DEVICES
@@ -3501,7 +3547,8 @@ bool DateTimeCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #ifdef USE_UPDATE
 void ListEntitiesUpdateResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
@@ -3530,7 +3577,8 @@ uint32_t ListEntitiesUpdateResponse::calculate_size() const {
   return size;
 }
 void UpdateStateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_fixed32(1, this->key, true);
+  buffer.write_raw_byte(13);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_bool(2, this->missing_state);
   buffer.encode_bool(3, this->in_progress);
   buffer.encode_bool(4, this->has_progress);
@@ -3642,7 +3690,8 @@ uint32_t ZWaveProxyRequest::calculate_size() const {
 #ifdef USE_INFRARED
 void ListEntitiesInfraredResponse::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_string(1, this->object_id);
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   buffer.encode_string(3, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(4, this->icon);
@@ -3717,7 +3766,8 @@ void InfraredRFReceiveEvent::encode(ProtoWriteBuffer &buffer) const {
 #ifdef USE_DEVICES
   buffer.encode_uint32(1, this->device_id);
 #endif
-  buffer.encode_fixed32(2, this->key, true);
+  buffer.write_raw_byte(21);
+  buffer.write_fixed32_raw(this->key);
   for (const auto &it : *this->timings) {
     buffer.encode_sint32(3, it, true);
   }

esphome/components/api/proto.h

@@ -236,6 +236,13 @@ class ProtoWriteBuffer {
    * Following https://protobuf.dev/programming-guides/encoding/#structure
    */
   void encode_field_raw(uint32_t field_id, uint32_t type) { this->encode_varint_raw((field_id << 3) | type); }
+  /// Write a single raw byte to the buffer (no tag, no encoding).
+  inline void write_raw_byte(uint8_t b) ESPHOME_ALWAYS_INLINE { *this->pos_++ = b; }
+  /// Write a raw 32-bit value in little-endian format (no tag, no zero check).
+  inline void write_fixed32_raw(uint32_t value) ESPHOME_ALWAYS_INLINE {
+    std::memcpy(this->pos_, &value, 4);
+    this->pos_ += 4;
+  }
   void encode_string(uint32_t field_id, const char *string, size_t len, bool force = false) {
     if (len == 0 && !force)
       return;
@@ -276,7 +283,7 @@ class ProtoWriteBuffer {
     this->debug_check_bounds_(1);
     *this->pos_++ = value ? 0x01 : 0x00;
   }
-  inline void encode_fixed32(uint32_t field_id, uint32_t value, bool force = false) ESPHOME_ALWAYS_INLINE {
+  void encode_fixed32(uint32_t field_id, uint32_t value, bool force = false) {
     if (value == 0 && !force)
       return;
 

script/api_protobuf/api_protobuf.py

@@ -556,6 +556,19 @@ class Fixed32Type(TypeInfo):
         o += "out.append(buffer);"
         return o
 
+    @property
+    def encode_content(self) -> str:
+        tag = (self.number << 3) | (self.wire_type & 0b111)
+        if self.force and tag < 128:
+            # Emit raw byte writes: precomputed tag + direct memcpy
+            return (
+                f"buffer.write_raw_byte({tag});\n"
+                f"buffer.write_fixed32_raw(this->{self.field_name});"
+            )
+        if self.force:
+            return f"buffer.{self.encode_func}({self.number}, this->{self.field_name}, true);"
+        return f"buffer.{self.encode_func}({self.number}, this->{self.field_name});"
+
     def get_size_calculation(self, name: str, force: bool = False) -> str:
         field_id_size = self.calculate_field_id_size()
         if force: