> ## Documentation Index
> Fetch the complete documentation index at: https://docs.struct.to/llms.txt
> Use this file to discover all available pages before exploring further.

# Response Format

> Understand how webhook payloads are structured.

Every webhook delivery sends a JSON payload to your configured endpoint. This structure is consistent across all event types.

## HTTP Headers

Each delivery is an HTTP `POST` carrying these headers:

| Header                | Description                                                                                                                                      |
| --------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------ |
| `X-Webhook-ID`        | UUID of the webhook subscription that produced the delivery.                                                                                     |
| `X-Delivery-ID`       | UUID of this specific delivery. Matches the `id` field in the body — use it to deduplicate.                                                      |
| `X-Event-Type`        | The event name, e.g. `trader_whale_trade`.                                                                                                       |
| `X-Attempt`           | Delivery attempt number, starting at `1`.                                                                                                        |
| `X-Webhook-Signature` | HMAC-SHA256 signature of the body, present only when the webhook has a `secret`. See [Signature Verification](/webhooks/signature-verification). |

## Payload Structure

```json theme={null}
{
  "id": "4aa4e020-818d-4a76-af9d-b023dd9674d2",
  "event": "trader_whale_trade",
  "data": { ... },
  "timestamp": 1773025181866,
  "webhook_id": "26cc4fb7-c62e-450c-a532-07196afd7b67",
  "attempt": 1
}
```

## Fields

### `id`

A unique identifier (UUID) for this specific webhook delivery. Use this to deduplicate events on your end.

### `event`

The event type that triggered this webhook. Matches one of the event types you subscribed to during setup.

### `data`

The event payload. Its shape depends on the `event` type. See the individual event documentation for field details.

### `timestamp`

Unix timestamp in milliseconds indicating when the event was emitted.

### `webhook_id`

The UUID of the webhook subscription that produced this delivery. Useful when you have multiple webhooks configured and need to identify the source.

### `attempt`

The delivery attempt number, starting at `1`. If your endpoint fails to respond with a `2xx` status code, Struct retries the delivery and increments this value.

## Retries & failures

A delivery succeeds only on a `2xx` response within the timeout. Otherwise it is retried:

| Property                | Value                                     |
| ----------------------- | ----------------------------------------- |
| Success criteria        | HTTP status `200`–`299`                   |
| Request timeout         | 30 seconds per attempt                    |
| Max attempts            | 10                                        |
| Backoff                 | 1 second between attempts                 |
| After all attempts fail | The webhook is automatically **disabled** |

<Warning>If 10 consecutive attempts fail, the subscription is set to `Disabled` and stops receiving events until you re-enable it with a `PUT /v1/webhooks/{id}`. Return `2xx` quickly — acknowledge first, then process the event out of band — so slow downstream work never trips the 30-second timeout.</Warning>

Because a delivery can be retried, the same event may arrive more than once. Deduplicate using the `id` field (or the `X-Delivery-ID` header).

<Note>Fields within `data` may be `null` depending on the event type and the availability of enriched metadata at the time of delivery.</Note>