Register webhook callback URL for async job notifications.

Webhook Events:

• job.completed - Job finished successfully
• job.failed - Job encountered error
• job.cancelled - Job was cancelled

Webhook Payload:

{
    "event": "job.completed",
    "job_id": "550e8400-e29b-41d4-a716-446655440000",
    "timestamp": "2025-01-08T12:00:25Z",
    "data": {
        "job_id": "550e8400-e29b-41d4-a716-446655440000",
        "status": "completed",
        "result": {...}
    }
}

Signature Verification:

• HMAC-SHA256 signature in X-Bellator-Signature header
• Format: sha256=<hex_signature>
• Payload: JSON-serialized webhook payload (deterministic order)

Delivery Guarantees:

• At-least-once delivery
• Max 3 retry attempts with exponential backoff
• 5 second initial retry delay, 15 second max delay
• Target delivery: <5 seconds after job completion

Best Practices:

• Return 2xx status code quickly (<1 second)
• Process webhook payload asynchronously
• Verify signature if secret provided
• Implement idempotency using job_id

{
  "events": [
    "job.completed",
    "job.failed"
  ],
  "secret": "whsec_abc123",
  "url": "https://customer.example.com/webhooks/bellator"
}