curl -X POST "https://api.voicecheap.ai/v1/projects" \
  -H "x-api-key: vc_your-key" \
  -F "file=@interview.mp4" \
  -F "targetLanguage=german" \
  -F "webhookUrl=https://staging.your-server.com/voicecheap/webhooks"

{
  "type": "project.created",
  "eventId": "evt_9f2c4b1d8e7a4c3f9b2d1e0a5c6b7d8e",
  "projectId": "7fa7d3a3-4f2b-4c1e-9a6d-2b3c4d5e6f70",
  "workflow": "transcription",
  "status": "success",
  "targetLanguage": "german",
  "error": null,
  "occurredAt": "2026-08-19T09:12:00.000Z"
}

import crypto from 'crypto';
import express from 'express';

const app = express();

// The raw body is required: parsing and re-serializing changes the bytes and the signature will
// never match. This is the single most common cause of failed verification.
app.post('/voicecheap/webhooks', express.raw({ type: 'application/json' }), (req, res) => {
  const rawBody = req.body.toString('utf8');
  const timestamp = req.header('X-VoiceCheap-Timestamp');
  const signature = req.header('X-VoiceCheap-Signature')?.replace('sha256=', '') ?? '';

  // Reject anything older than five minutes.
  if (Math.abs(Date.now() / 1000 - Number(timestamp)) > 300) {
    return res.status(400).send('Stale timestamp');
  }

  const expected = crypto
    .createHmac('sha256', process.env.VOICECHEAP_WEBHOOK_SECRET)
    .update(`${timestamp}.${rawBody}`)
    .digest('hex');

  const isValid =
    expected.length === signature.length &&
    crypto.timingSafeEqual(Buffer.from(expected), Buffer.from(signature));

  if (!isValid) return res.status(401).send('Invalid signature');

  const event = JSON.parse(rawBody);
  // Acknowledge quickly, then process asynchronously.
  res.status(200).send('ok');
  handleEvent(event);
});