How can I send POST request data from Android to node server?

If I transfer the data from Android to node server, I want to send fcm message with the data I received from the server using timer.

<a> http.createServer((req, res) => {</a>
<a>  res.write('Hello Node!');</br>
  setTimeout(sendFCM, 10000);</br>
  res.end('hello world!\n');</br>
}).listen(4999, () => {</br>
  console.log ('Waiting for fcm on port 4999);</br>
})</br>

When you click the IP and port on the webpage, the function functions normally. When a POST request is received from the client to the port, I would like to interpret the ('content-type', 'application/json; utf=8') type on the web server and deliver the necessary parameters to the FCM. (Actually, I don't know much about grammar) I'd appreciate it if you could write or reply to me!