Support and resources

Testing Your Webhook

Use the Webhook Test feature in SCALAR to validate your setup:

1. Navigate to your subscription
2. Click Test Connection
3. SCALAR sends a test event batch to your endpoint
4. Verify you receive the request
5. Confirm your endpoint returns 200 status code
6. Check that test data is processed correctly

Common Questions

Q: How long does SCALAR retain events if my webhook is down?

With overflow protection enabled, SCALAR can buffer events for up to 7 days. But oldest events start being dropped in every 24 hours.

Q: How can I validate that requests are from SCALAR?

Use HMAC signature validation. Extract the signature from the X-SCALAR-SIGNATURE header and verify it against your webhook secret. Always validate signatures before processing events.

Q: Can I change my webhook URL after creating a subscription?

Yes. You can update the webhook URL in the subscription settings. The change takes effect for new event batches. Existing in-flight batches may still go to the old endpoint.

Q: What's the maximum batch size?

The maximum batch size is 500 events. You can configure smaller batch sizes if needed. Smaller batches mean more frequent deliveries but lower latency per event.

Q: How do I add custom headers for my internal systems?

In subscription settings, add up to 5 custom headers. Each header includes a key and value. Custom headers are included in all webhook requests to your endpoint.

Q: What happens if my webhook endpoint is down?

SCALAR automatically retries failed deliveries with exponential backoff. After 5 failed retries, the subscription status changes to "onHold" and events are buffered if Overflow is enabled otherwise it will deactivate the subscription. Once your endpoint is back online, reactivate the subscription to resume delivery.