WebSocket API

Documentation for https://www.jdoodle.com/compiler-api/

How WebSocket API is different from the REST API

REST API does not support interactive program execution - you have to send all the required input along with the program which is good for some use cases (similar to the non-interactive mode in JDoodle.com). With Websocket API, you can provide an interactive experience to the user like they run a program in their local machine (similar to interactive mode in JDoodle).

How can I make a Websocket call?

Running a WebSocket API is a two-step process.

  1. Get auth token from JDoodle by passing by calling https://api.jdoodle.com/v1/auth-token endpoint with your Client ID/Secret. The token is valid for 180 seconds. You need to make this call from your server to JDoodle.

  2. Using the token you received in step 1, will call WebSocket Endpoint from the browser to provide an interactive experience to the user.

WebSocket call flow

Input Parameters for the "get-token" API call




Client ID for your subscription


Client Secret for your subscription

Output Parameters for the "credit-spent" API call when the execution is successful

The response contains the token in the body.

Output Parameters for the "credit-spent" API call when the execution failed




error message


Status Code of the result

Integrating WebSocket requests to your Website

Below is a sample implementation of WebSocket in a standalone HTML file. This is pretty much self-explanatory. You have to replace the token with the token you receive in the "auth-token" request.


output <br/>
<textarea rows="5" cols="100" id="result" onkeypress="onInput(event)"></textarea>

<script src="https://api.jdoodle.com/js/sockjs.js"></script>
<script src="https://api.jdoodle.com/js/webstomp.js"></script>

let socketClient = webstomp.over(new SockJS('https://api.jdoodle.com/v1/stomp'), { heartbeat: false, debug: true })

function onWsConnection() {
  console.log('connection succeeded')

  socketClient.subscribe('/user/queue/execute-i', (message) => {
        let msgId = message.headers['message-id']
        let msgSeq = parseInt(msgId.substring(msgId.lastIndexOf('-') + 1))

        let statusCode = parseInt(message.headers.statusCode)

        if (statusCode === 201) {
          this.wsNextId = msgSeq + 1

        let t0
        try {
          t0 = performance.now()
          while ((performance.now() - t0) < 2500 && this.wsNextId !== msgSeq) {

        } catch (e) {


        if (statusCode === 204) {
          //executionTime = message.body
        } else if (statusCode === 500 || statusCode === 410) {
          //server error
          console.log("server error");
        } else if (statusCode === 206) {
          //outputFiles = JSON.parse(message.body)
          //returns file list - not supported in this custom api
        } else if (statusCode === 429) {
          //Daily limit reached
          console.log("daily limit reached");
        } else if (statusCode === 400) {
          //Invalid request - invalid signature or token expired - check the body for details
          console.log("invalid request - invalid signature or token expired");
        } else if (statusCode === 401) {
          //Unauthorised request
          console.log("Unauthorised request");
        } else {
          var txt = document.getElementById("result").value
          document.getElementById("result").value = txt + message.body

        this.wsNextId = msgSeq + 1

    let script =  ` import java.util.Scanner;
 import java.util.NoSuchElementException;

public class MyClass {
 public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);

		try {
		 System.out.println("Type a Line and enter....");
		String txt = scanner.nextLine();
		System.out.println("You have typed...");
		} catch (NoSuchElementException e) {
		    System.out.println("Type something in the Stdin box above....");


    let data = JSON.stringify({
            script: script,
            language: "java",
            versionIndex: 4

    socketClient.send('/app/execute-ws-api-token', data, { message_type: 'execute', token: "eyJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJKRE9PRExFIiwic3ViIjoiV1MtQVBJLVRPS0VOIiwiY2xpZW50LWlkIjoiODk0ZGVhYmQ1ZGYwZDBmZGE0NmZjZDI5NGM0ZTZmNmEiLCJpYXQiOjE2Nzg4ODQ0MDYsImV4cCI6MTY3ODg4NDU4Nn0.Vp2rqQ9HQxtxq1XcuQtWSkmHA21GiJbZltNs49zqlAs" })

function onWsConnectionFailed(e) {
  console.log('connection failed')

function onInput(e) {
  let key = event.key
  if (event.key === 'Enter') {
    key = '\n'
  socketClient.send('/app/execute-ws-api-token', key, { message_type: 'input' })


socketClient.connect({}, onWsConnection, onWsConnectionFailed)

More details on languages, versions, credit-spent, etc

Please refer our REST API documentation.

Where can I find help and support?

For any help, doubts, suggestions, etc. Please get in touch with us at hello@jdoodle.com

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