Problem
GC sits at 2024-11.940.0. The BYOC deployment uses AWS PrivateLink for outbound connectivity, but the webhook delivery keeps failing the JWT check on the Express listener. Traffic routes through the Genesys Edge proxy before hitting the ALB in the private VPC. The middleware catches routing.queue.empty events fine when testing locally, but once it hits the production Edge path, the x-gc-signature header arrives mangled or completely absent on about 30% of the payloads.
JWT validation uses the standard jsonwebtoken library with the org secret pulled from env vars. The payload itself looks intact, but the signature verification throws a mismatch error. CloudWatch logs show the Express route processing the request, then immediately rejecting it with a 401. The GC webhook dashboard marks those deliveries as FAILED with a JWT_INVALID status. The queue backlogs up fast.
app.post('/webhooks/gc', express.json({ verify: (req, res, buf) => { req.rawBody = buf } }), (req, res) => {
const signature = req.headers['x-gc-signature'];
const body = req.rawBody.toString();
try {
jwt.verify(signature, process.env.GC_ORG_SECRET, { algorithms: ['HS256'] });
console.log('JWT valid, processing event:', req.body.eventType);
res.status(200).send('OK');
} catch (err) {
console.error('JWT verification failed:', err.message);
res.status(401).send('Unauthorized');
}
});
Error log from the Express container:
JWT verification failed: invalid signature
[2024-11-15T14:22:18.301-06:00] POST /webhooks/gc 401 12ms - 6.12 KB
[2024-11-15T14:22:19.005-06:00] POST /webhooks/gc 200 8ms - 4.21 KB
The raw body matches the signature when running a quick openssl dgst -sha256 -hmac check, but the header coming from the Edge endpoint has trailing whitespace or gets URL-encoded somewhere in the proxy chain. GC documentation mentions the Edge layer should pass headers through untouched. Switching the webhook to a public AWS endpoint bypasses the issue completely, so it’s definitely tied to the BYOC VPC routing or the PrivateLink interface. The middleware times out waiting for a retry and just sits there doing jack all until GC gives up on the delivery.
Checking the VPC flow logs shows the traffic hits the ALB, but the header count drops by one on the failed requests. You’ll notice the x-gc-signature key vanishes right at the TLS termination point. Don’t know if the Edge proxy is stripping it or if there’s a known quirk with how Genesys signs payloads when routing through private endpoints. Raw payload dump from the failed request:
{
"eventType": "routing.queue.empty",
"eventDate": "2024-11-15T14:22:18.301-06:00",
"queueId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
"queueName": "Support-Queue-01",
"memberCount": 0
}