Webhook

PHP

$secret = getenv('CRYBIT_WEBHOOK_SECRET');
$body   = file_get_contents('php://input');
$header = $_SERVER['HTTP_X_CRYBIT_SIGNATURE'] ?? '';

parse_str(str_replace(',', '&', $header), $p);   // t=…&v1=…
$t = (int) ($p['t'] ?? 0);
$expected = hash_hmac('sha256', $t . '.' . $body, $secret);

if (abs(time() - $t) > 300 || !hash_equals($expected, $p['v1'] ?? '')) {
    http_response_code(400);
    exit;
}
// the request is genuine: store the event, answer 200, do the rest later
http_response_code(200);

Node.js

import crypto from 'node:crypto'

export function verify(rawBody, header, secret) {
  const parts = Object.fromEntries(header.split(',').map((kv) => kv.split('=')))
  const t = Number(parts.t)
  const expected = crypto.createHmac('sha256', secret).update(t + '.' + rawBody).digest('hex')
  const ok = parts.v1 && parts.v1.length === expected.length
    && crypto.timingSafeEqual(Buffer.from(parts.v1), Buffer.from(expected))
  return ok && Math.abs(Date.now() / 1000 - t) <= 300
}