Webhooks

Subscribe to events. We POST a JSON payload to your URL when events occur.

Signature verification

Header: kappabuf-Signature: t=1714060800,v1=abc123...

Compute HMAC-SHA256(secret, payload) and compare to v1 value.

Event types

• charge.succeeded
• charge.failed
• refund.created
• customer.deleted

Retries

If your endpoint returns non-2xx, we retry with exponential backoff for 24h.