📑Events Catalog

Webhook events supported by Docs-Dispatcher providers.

Overview

Docs-Dispatcher supports webhooks for 3 providers across 2 services.

Webhooks enable:

• Real-time notifications when events occur

• Automated workflows based on provider responses

• Asynchronous processing with status updates

• Error tracking and retry logic

Supported Services

Service	Providers with Webhooks	Total Events
Esign	Signaturit, Universign	8
Postal	Mysendingbox	5

Events by Service

Esign

👉 Esign Webhook Documentation

Signaturit:

• document_signed - Document has been signed by all signatories

• document_declined - Document was declined by a signatory

• document_expired - Document signing deadline expired

• document_canceled - Document was canceled

Universign:

• transaction_completed - Signature transaction completed successfully

• transaction_failed - Signature transaction failed

• transaction_canceled - Signature transaction was canceled

• signer_signed - Individual signer completed their signature

Postal

👉 Postal Webhook Documentation

Mysendingbox:

• letter_created - Letter was created and queued

• letter_in_transit - Letter is in transit to recipient

• letter_delivered - Letter was delivered

• letter_failed - Letter delivery failed

• letter_returned - Letter was returned to sender

Webhook URL Pattern

All webhook callbacks follow this URL pattern:

POST /api/webhooks/{service}/providers/{provider}/endpoint.json

Examples:

• POST /api/webhooks/esign/providers/signaturit/endpoint.json

• POST /api/webhooks/esign/providers/universign/endpoint.json

• POST /api/webhooks/postal/providers/mysendingbox/endpoint.json

Webhook Payload Structure

All webhooks include:

{
  "event": "event_name",
  "timestamp": "2026-02-13T12:30:00Z",
  "dispatchId": "disp_abc123",
  "provider": "provider_name",
  "service": "service_name",
  "data": {
    // Event-specific data
  }
}

Webhook Security

Signature Verification: All webhooks include an X-Webhook-Signature header for verification:

X-Webhook-Signature: sha256=abc123def456...

Verification Example (Node.js):

const crypto = require('crypto');

function verifyWebhookSignature(payload, signature, secret) {
  const hmac = crypto.createHmac('sha256', secret);
  hmac.update(JSON.stringify(payload));
  const expected = 'sha256=' + hmac.digest('hex');
  return crypto.timingSafeEqual(
    Buffer.from(signature),
    Buffer.from(expected)
  );
}

Next Steps

• Webhook Fundamentals - Setup and configuration

• Esign Webhooks

• Postal Webhooks

• Async Dispatch Recipe - Using webhooks with async dispatch