---
updatedAt: 2026-05-20T16:31:19.000Z
---

Fetch the complete documentation index at: https://docs.blockdaemon.com/llms.txt. Use this file to discover all available pages before exploring further. Append .md to any documentation page URL to get its markdown version.

# Webhook Handling

### Delivery Failures

A webhook can fail to deliver messages if it receives a non-2xx status code for 10 consecutive delivery attempts. Each delivery attempt has an exponential backoff with a maximum period of one minute.

* **Failure Handling**: When delivery fails, the webhook's status is changed to "**failed**." No further messages are delivered until the verification process is completed. However, messages are still added to the target's topic to prevent data loss when reconnecting.
* **Reconnection**: Failed or active targets periodically receive a CRC request every 10 minutes. Upon successful verification, the target's status changes to "**connected**." A system message and backlogged messages will be sent to the target, followed by new messages as shown below.

```json
{
    "protocol": "system",
    "event_type": "system.connection"
    "data": {
        "target_id": "ddfc2e56-f82c-4a24-975e-427230242476",
        "disconnect_time": "2023-07-29T17:37:38.242292Z",
        "connection_time": "2023-07-29T17:39:18.725464Z",
        "previous_status": "failed",
        "new_status": "connected"
    }
}
```

> 📘 Info:
>
> The number of delivery attempts may be more than 10 in the event of a rolling upgrade of our services.

### Message Drops

Each target’s topic has a maximum size that if exceeded because of slow processing or the target being unable to accept messages will result in older messages being dropped.

If messages are dropped, a notification is sent to the user as a "**dropped message**" event.

```json
{
  "protocol": "system",
  "event_type": "system.dropped.messages",
  "data": {
    "dropped_msg_count": 1,
    "pending_msg_count": 100,
    "target_id": "85366adb-7550-400a-889f-3ae46f4b7668",
    "time": "2023-07-29T16:09:31.045872283Z"
  }
}
```

The current maximum number of messages is 10,000. The number of buffered messages per target can be controlled using the `max_buffer_count` parameter.

## 👋 Need Help?

Contact us through [email](mailto:support@blockdaemon.com) or our [support page](https://www.blockdaemon.com/support) for any issues, bugs, or assistance you may need.