# Errors

Source: https://developers.swell.is/backend-api/errors

Swell uses standard HTTP status codes to indicate the success or failure of an API request. A code in the range of `2xx` indicates success, a code in the range of `4xx` indicates there was a problem with the arguments provided (e.g., a required field was missing), and a code in the range of `5xx` indicates an error occurred with Swell's servers.

## Validation errors

A validation error object is returned when a request could not be fulfilled due to one or more invalid values.

### Fields

- `code` (string): A distinct code indicating the cause of the error.
- `message` (string): A human-readable description of the error.
- `params` (object): Object containing parameter values related to the error.

### Example response

```json
{
  "errors": {
    "name": {
      "code": "REQUIRED",
      "message": "Required"
    },
    "email": {
      "code": "FORMAT_EMAIL",
      "message": "Must be a valid email address"
    }
  }
}
```


## Handling errors

Swell API libraries return a [validation error](https://developers.swell.is/backend-api/errors/validation-errors) object in case of an invalid `PUT`, `POST`, or `DELETE` request, and *throw* in any other error case.

#### Status codes

Failed requests return a standard HTTP status code along with a message describing what went wrong.

| Status | Meaning |
| --- | --- |
| 400 | The request was malformed, or exceeded a documented limit. |
| 402 | The store's plan or trial has expired and must be renewed to continue using the API. |
| 403 | The credentials used aren't authorized for that resource. |
| 404 | No resource exists at that path. |
| 405 | The endpoint doesn't support that HTTP method. |
| 429 | The request was rate limited. |

A `429` means the request waited too long for capacity rather than that it was rejected outright — see [rate limits](https://developers.swell.is/backend-api/rate-limits) for how requests are weighted and how to back off.

Two endpoints report errors differently from the rest. [Transactions](https://developers.swell.is/backend-api/transactions) return typed error codes such as `transaction_conflict` and `transaction_timeout`, and roll back completely when any operation fails. In a [batch](https://developers.swell.is/backend-api/batch-requests), a failed operation returns an `$error` in its own slot of the response while the other operations still apply, so each entry has to be checked individually.