diff --git a/platformio.ini b/platformio.ini
index 8c4f194..0263ce2 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -18,6 +18,7 @@ lib_deps =
 	Adafruit GFX Library@~1.7.5
 	ArduinoNvs@~2.5
 	ESP Async WebServer@~1.2.3
+	ArduinoJson@~6.14.1
 
   # Semantic Versioning Rules
   # http://docs.platformio.org/page/userguide/lib/cmd_install.html#description
diff --git a/src/app.cpp b/src/app.cpp
index 74b15ac..5c7b2cb 100644
--- a/src/app.cpp
+++ b/src/app.cpp
@@ -1,6 +1,8 @@
 #include "app.h"
 #include "SPIFFS.h"
 #include "ESPAsyncWebServer.h"
+#include "AsyncJson.h"
+#include "ArduinoJson.h"
 
 // https://techtutorialsx.com/2018/09/17/esp32-arduino-web-server-serving-external-css-file/
 // https://docs.platformio.org/en/latest/platforms/espressif8266.html#uploading-files-to-file-system-spiffs
@@ -27,6 +29,29 @@ void setupApp()
 		.setCacheControl("max-age=600")
 	;
 
+
+	// TODO response
+	server.on("/test", HTTP_GET, [] (AsyncWebServerRequest *request) {
+		AsyncResponseStream *response = request->beginResponseStream("application/json");
+
+		DynamicJsonDocument root(1024);
+		root["heap"] = ESP.getFreeHeap();
+		root["ssid"] = WiFi.SSID();
+
+		serializeJson(root, *response);
+		request->send(response);
+    });
+
+
+	// TODO request
+	AsyncCallbackJsonWebHandler* handler = new AsyncCallbackJsonWebHandler("/rest/endpoint", [](AsyncWebServerRequest *request, JsonVariant &json) {
+		JsonObject jsonObj = json.to<JsonObject>();
+
+
+		// ...
+	});
+	server.addHandler(handler);
+
 	server.begin();
 
 	Serial.println("setup configure - done");