diff --git a/src/mqtt.cpp b/src/mqtt.cpp
index 3a3acfb3f..ea6dec345 100644
--- a/src/mqtt.cpp
+++ b/src/mqtt.cpp
@@ -789,8 +789,11 @@ void Mqtt::register_mqtt_ha_sensor(const char *                prefix,
     }
     new_name[0] = toupper(new_name[0]); // capitalize first letter
 
+#if defined(ESP32)
+    StaticJsonDocument<EMSESP_MAX_JSON_SIZE_HA_CONFIG> doc;
+#else
     DynamicJsonDocument doc(EMSESP_MAX_JSON_SIZE_HA_CONFIG);
-
+#endif
     doc["name"]    = new_name;
     doc["uniq_id"] = uniq;
     if (uom != nullptr) {
@@ -805,9 +808,14 @@ void Mqtt::register_mqtt_ha_sensor(const char *                prefix,
     JsonArray  ids = dev.createNestedArray("ids");
     ids.add(ha_device);
 
+#if defined(ESP32)
+    // queue MQTT publish
+    publish_retain(topic, doc.as<JsonObject>(), true);
+#else
     // convert json to string and publish immediately with retain forced to true
     std::string payload_text;
     serializeJson(doc, payload_text); // convert json to string
+
     uint16_t packet_id = mqttClient_->publish(topic, 0, true, payload_text.c_str());
     if (!packet_id) {
         LOG_ERROR(F("Failed to publish topic %s"), topic);
@@ -820,6 +828,7 @@ void Mqtt::register_mqtt_ha_sensor(const char *                prefix,
     }
 
     delay(50); // enough time to send the short message out
+#endif
 }
 
 } // namespace emsesp
diff --git a/src/mqtt.h b/src/mqtt.h
index 41e2899f6..7d2decdc3 100644
--- a/src/mqtt.h
+++ b/src/mqtt.h
@@ -39,7 +39,7 @@
 using uuid::console::Shell;
 
 #define EMSESP_MAX_JSON_SIZE_HA_CONFIG 384 // for small HA config payloads
-#define EMSESP_MAX_JSON_SIZE_SMALL 384     // for smaller json docs when using StaticJsonDocument
+#define EMSESP_MAX_JSON_SIZE_SMALL 256     // for smaller json docs when using StaticJsonDocument
 #define EMSESP_MAX_JSON_SIZE_MEDIUM 768    // for medium json docs from ems devices, when using StaticJsonDocument
 #define EMSESP_MAX_JSON_SIZE_LARGE 1024    // for large json docs from ems devices, like boiler or thermostat data. Using StaticJsonDocument
 #define EMSESP_MAX_JSON_SIZE_DYN 2048      // for large json docs from web. Using DynamicJsonDocument
@@ -176,6 +176,8 @@ class Mqtt {
 
 #if defined(EMSESP_STANDALONE)
     static constexpr size_t MAX_MQTT_MESSAGES = 70; // size of queue
+#elif defined(ESP32)
+    static constexpr size_t MAX_MQTT_MESSAGES = 100; // size of queue
 #else
     static constexpr size_t MAX_MQTT_MESSAGES = 20; // size of queue
 #endif