🟢 Node.js example

import crypto from 'node:crypto';
import axios from 'axios';

const ENDPOINT = 'https://bbb.example.com/bigbluebutton/api';
const SECRET   = 'YOUR_SHARED_SECRET';

async function main() {
  // 1) Query string for create (checksum uses ONLY the query)
  const params = new URLSearchParams({
    name: 'Demo with Overrides',
    meetingID: 'demo-123',
    attendeePW: 'ap',
    moderatorPW: 'mp',
    allowOverrideClientSettingsOnCreateCall: 'true',
  });
  const query = params.toString();

  // 2) checksum = sha1('create' + query + secret)
  const checksum = crypto.createHash('sha1')
    .update('create' + query + SECRET)
    .digest('hex');

  const url = `${ENDPOINT}/create?${query}&checksum=${checksum}`;

  // 3) JSON override in CDATA
  const override = {
    public: {
      app: { appName: 'Greenlight', helpLink: 'greenlight.example.com' },
      defaultSettings: {
        application: { autoJoin: true, askForConfirmationOnLeave: false },
        user: { userSettingsStorage: 'sessionStorage', application: { overrideLocale: 'en' } },
      },
    },
  };

  const xmlBody =
    `<modules><module name="clientSettingsOverride"><![CDATA[${JSON.stringify(override)}]]></module></modules>`;

  // 4) POST it
  const { data } = await axios.post(url, xmlBody, {
    headers: { 'Content-Type': 'application/xml' },
    timeout: 30000,
  });

  console.log(data); // XML response
}

main().catch(err => {
  console.error(err);
  process.exit(1);
});