Install `@aws-sdk/client-ivs-realtime`, `@aws-sdk/client-ivschat` and run with `node simple-ivs-token-service.js`.

simple-ivs-token-service.js

import * as http from 'http';
import * as url from 'url';
import { CreateParticipantTokenCommand, IVSRealTimeClient } from "@aws-sdk/client-ivs-realtime";
import { CreateChatTokenCommand, IvschatClient } from "@aws-sdk/client-ivschat";

const ivsChatClient = new IvschatClient();
const ivsRealtimeClient = new IVSRealTimeClient();

const createChatToken = async (chatArn, userId, username) => {
  const chatTokenInput = {
    roomIdentifier: chatArn,
    userId,
    attributes: { username },
    capabilities: ['SEND_MESSAGE'],
    sessionDurationInMinutes: 180,
  };
  const createChatTokenRequest = new CreateChatTokenCommand(chatTokenInput);
  return await ivsChatClient.send(createChatTokenRequest);
};

const createStageToken = async (stageArn, attributes, capabilities, userId, duration) => {
  const createStageTokenRequest = new CreateParticipantTokenCommand({
    attributes,
    capabilities,
    userId,
    stageArn,
    duration,
  });
  const createStageTokenResponse = await ivsRealtimeClient.send(createStageTokenRequest);
  return createStageTokenResponse;
};

async function handler(req, res) {
  const parsedUrl = url.parse(req.url, true);
  if (parsedUrl.pathname === '/token') {
    let body = '';
    req.on('data', chunk => {
      body += chunk.toString();
    });
    req.on('end', async () => {
      const params = JSON.parse(body);
      res.writeHead(200, { 'Content-type': 'application/json' });
      const tokenResponse = await createStageToken(
        params.stageArn,
        params.attributes,
        params.capabilities,
        params.userId,
        params.duration,
      );
      res.write(JSON.stringify(tokenResponse));
      res.end();
    });
  }
  else if (parsedUrl.pathname === '/chat-token') {
    let body = '';
    req.on('data', chunk => {
      body += chunk.toString();
    });
    req.on('end', async () => {
      const params = JSON.parse(body);
      res.writeHead(200, { 'Content-type': 'application/json' });
      const tokenResponse = await createChatToken(
        params.chatArn,
        params.username,
        params.userId,
      );
      res.write(JSON.stringify(tokenResponse));
      res.end();
    });
  }
  else {
    res.writeHead(404, { 'Content-type': 'text/plain' });
    res.write('404 Not Found');
    res.end();
  };
}

const server = http.createServer(handler);
server.listen(3000);