ESP_Server

#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>
#include <ESP8266mDNS.h>

const char *ssid = "DataJugling";
const char *password = "jugle123";
const char *mDNS = "dataserver";

ESP8266WebServer server(80);

bool ledState = LOW;

String getData() {
  return String("{\"state\": ") + String(ledState) + String("}");
}

void setup() {
  WiFi.mode(WIFI_AP);
  WiFi.softAP(ssid, password);
  MDNS.begin(mDNS);

  server.on("/", []() {
    server.send(200, "text/html", getData());
  });

  server.begin();
}

void loop() {
  server.handleClient();
  if(millis() % 1000 == 0) ledState = !ledState;
}