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

# Response format

> Standard JSON envelope for Wapilot Developer API success and error responses.

## Envelope

Successful and error responses use a consistent **JSON** shape (see `ApiResponse` in the backend):

| Field     | Type           | Description                                              |
| --------- | -------------- | -------------------------------------------------------- |
| `status`  | number         | HTTP status code (also reflected in the response status) |
| `success` | boolean        | `true` for success, `false` for errors                   |
| `message` | string         | Human-readable summary                                   |
| `data`    | object \| null | Payload on success; often `null` on error                |
| `errors`  | array          | Validation or detailed errors; often `[]` when unused    |

## Success example

```json theme={null}
{
  "status": 200,
  "success": true,
  "message": "Contacts retrieved successfully",
  "data": { "rows": [], "meta": {} },
  "errors": []
}
```

The exact `data` object depends on the endpoint (list results, a single record, a send receipt, etc.).

## Error example

```json theme={null}
{
  "status": 400,
  "success": false,
  "message": "The phone number is not valid.",
  "data": null,
  "errors": []
}
```

## BigInt and JSON

The server serializes **BigInt** values in JSON responses so numeric IDs from the database are safe for clients. If you see large integers, treat them as numbers or strings according to your client’s needs.

## Related

* [Authentication](/developer-api/authentication) — 401/403 response messages for API key and plan issues