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

# Authentication

> Learn what it takes to authenticate to the Square Cloud API.

First you need to get an API key from the [Developer Dashboard](https://squarecloud.app/en/account/security). You can use this API key to authenticate to the Square Cloud API.

```bash theme={null}
'Authorization': '<api_key>'
```

## API Usage

You can use the API key to authenticate to the Square Cloud API. You can use the API key in the `Authorization` header.
Remembering that the use of the API is subject to the [Terms of Service](https://squarecloud.app/legal) and the [Acceptable Use Policy](https://squarecloud.app/legal/policy).

## Error codes

Error responses follow the shape `{ "status": "error", "code": "SOME_CODE" }`. In July 2026 several codes were renamed to a consistent convention (`INVALID_X`, `X_NOT_FOUND`, `X_FAILED`, `X_LIMIT_REACHED`): see the [changelog](/en/changelog) for the full mapping.

```json theme={null}
{
    "status": "error",
    "code": "RATE_LIMITED"
}
```

### Global errors

Any Blob route can also return these:

| Code                            | HTTP | Meaning                                                                                                       |
| ------------------------------- | ---- | ------------------------------------------------------------------------------------------------------------- |
| `ACCESS_DENIED`                 | 401  | The API key is missing or invalid.                                                                            |
| `RATE_LIMIT`                    | 429  | Global rate limit of the authentication layer. Note the exact name: per-route rate limits use `RATE_LIMITED`. |
| `ROUTE_NOT_FOUND` / `NOT_FOUND` | 404  | The requested route does not exist.                                                                           |
| `INTERNAL_SERVER_ERROR`         | 500  | Unexpected internal failure. Try again later.                                                                 |

<Card title="Limits and Restrictions" href="/en/api-reference/limitations-and-restrictions">
  Learn about the limits and restrictions of the Square Cloud API.
</Card>