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

# Webhook Payload Reference

> Everything you need to know about webhook payloads and how to handle them.

## Webhook Delivery

When an event wraps up, each::labs fires off an HTTP POST to your configured `webhook_url`.

* **Method:** `POST`
* **Content-Type:** `application/json`
* **Expected response:** `200 OK` to acknowledge receipt

## Payload Structure

### Prediction Complete

```json theme={"dark"}
{
  "id": "abc123-def456-ghi789",
  "status": "success",
  "output": "https://storage.example.com/predictions/abc123/image.jpg",
  "input": {
    "prompt": "A beautiful sunset over the ocean",
    "aspect_ratio": "16:9"
  },
  "metrics": {
    "predict_time": 12.5,
    "cost": 0.05
  }
}
```

### Prediction Failed

```json theme={"dark"}
{
  "id": "abc123-def456-ghi789",
  "status": "failed",
  "output": null,
  "input": {
    "prompt": "A beautiful sunset over the ocean",
    "aspect_ratio": "16:9"
  },
  "logs": "Error: Model timeout after 30s"
}
```

## Webhook Handler Examples

<CodeGroup>
  ```python Python (FastAPI) theme={"dark"}
  from fastapi import FastAPI, Request

  app = FastAPI()

  @app.post("/webhooks/prediction")
  async def handle_webhook(request: Request):
      payload = await request.json()

      if payload["status"] == "success":
          output_url = payload["output"]
          print(f"Prediction complete: {output_url}")
          # Process the output...
      elif payload["status"] == "failed":
          print(f"Prediction failed: {payload.get('logs')}")

      return {"received": True}
  ```

  ```javascript JavaScript (Express) theme={"dark"}
  app.post("/webhooks/prediction", (req, res) => {
    const payload = req.body;

    if (payload.status === "success") {
      console.log(`Prediction complete: ${payload.output}`);
      // Process the output...
    } else if (payload.status === "failed") {
      console.log(`Prediction failed: ${payload.logs}`);
    }

    res.json({ received: true });
  });
  ```
</CodeGroup>

## Security

### Webhook Secret Verification

If you set a `webhook_secret` when creating your prediction, you can use it to make sure incoming webhooks are legit.

```python theme={"dark"}
import hmac
import hashlib

def verify_webhook(payload_body: bytes, signature: str, secret: str) -> bool:
    expected = hmac.new(
        secret.encode(),
        payload_body,
        hashlib.sha256
    ).hexdigest()
    return hmac.compare_digest(expected, signature)
```

## Retry Behavior

| Attempt   | Delay        |
| --------- | ------------ |
| 1st retry | \~30 seconds |
| 2nd retry | \~2 minutes  |
| 3rd retry | \~10 minutes |

Retries stop after all attempts are used up. Use [Get Webhook](/api/webhooks/get-webhook) to check out the full delivery history.

## Best Practices

* Return `200 OK` as fast as you can, then process data asynchronously
* Implement idempotency, since you may receive the same webhook more than once
* Log incoming payloads for debugging
* Use `webhook_secret` to verify payload authenticity
* Set up monitoring for your webhook endpoint's availability