> For the complete documentation index, see [llms.txt](https://help.alternativepayments.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.alternativepayments.io/getting-started/accounts-payable-api/webhooks.md).

# Webhooks

The Accounts Payable API adds 14 new webhook topics to the existing webhook infrastructure. Partners subscribe using the same `POST /webhooks` endpoint with new topic values. No new webhook endpoints are needed.

## Subscribing to Acc Payable Webhooks

Use the existing webhook subscription endpoint:

```
POST /webhooks
```

```json
{
  "topic": "vendor_created",
  "endpoint_url": "https://your-server.com/webhooks",
  "secret_key": "your-webhook-secret"
}
```

## New Webhook Topics

### Vendor Events

| Topic                | Trigger                                           |
| -------------------- | ------------------------------------------------- |
| `vendor_created`     | Vendor created (manual, OCR, or integration sync) |
| `vendor_updated`     | Vendor details changed                            |
| `vendor_deactivated` | Vendor deactivated                                |
| `vendor_reactivated` | Vendor reactivated                                |

### Bill Events

| Topic            | Trigger                                         |
| ---------------- | ----------------------------------------------- |
| `bill_created`   | Bill created (manual, OCR, or integration sync) |
| `bill_updated`   | Bill details changed                            |
| `bill_submitted` | Bill submitted for approval                     |
| `bill_rejected`  | Bill rejected                                   |
| `bill_deleted`   | Bill soft-deleted                               |

### Vendor Payment Events

| Topic                       | Trigger                                           |
| --------------------------- | ------------------------------------------------- |
| `vendor_payment_processing` | Vendor payment initiated, funds being transferred |
| `vendor_payment_succeeded`  | Vendor payment completed successfully             |
| `vendor_payment_failed`     | Vendor payment failed                             |
| `vendor_payment_canceled`   | Vendor payment canceled                           |

### Vendor Data Request Events

| Topic                           | Trigger                                                |
| ------------------------------- | ------------------------------------------------------ |
| `vendor_data_request_submitted` | Vendor completed the self-service data collection form |

## Webhook Payload Format

Webhook payloads follow the same format as existing AR webhooks. The `topic` field indicates the event type, and the `data` field contains the resource details.

```json
{
  "id": "event-uuid",
  "topic": "vendor_payment_succeeded",
  "created_at": "2026-04-15T14:30:00Z",
  "data": {
    "vendor_payment_id": "aa0e8400-e29b-41d4-a716-446655440000",
    "bill_id": "660e8400-e29b-41d4-a716-446655440000",
    "vendor_id": "550e8400-e29b-41d4-a716-446655440000",
    "payment_id": "990e8400-e29b-41d4-a716-446655440000",
    "partner_id": "bb0e8400-e29b-41d4-a716-446655440000",
    "amount": 1500.00,
    "payment_date": "2026-04-15T14:30:00Z"
  }
}
```

## Managing Webhook Subscriptions

All existing webhook management endpoints work with the new topics:

| Method | Path                    | Description                     |
| ------ | ----------------------- | ------------------------------- |
| POST   | `/webhooks`             | Subscribe to a topic            |
| GET    | `/webhooks`             | List subscriptions              |
| DELETE | `/webhooks/{id}`        | Unsubscribe                     |
| GET    | `/webhooks/{id}/events` | List events for a subscription  |
| POST   | `/webhooks/{id}/retry`  | Retry failed webhook deliveries |

## Webhook Delivery

* Webhooks are delivered via HTTP POST to the configured `endpoint_url`
* If a `secret_key` was provided, the payload is signed using HMAC-SHA256
* Failed deliveries are retried with exponential backoff
* Event history is retained for 30 days


---

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