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

# Authentication

> Use project API keys to authenticate Arc Studio API requests.

Create project API keys in Arc Studio under project settings, **API**.

The full key is shown once. Store it in a secrets manager or environment variable.

```bash theme={null}
export ARC_STUDIO_API_KEY="YOUR_API_KEY"
```

Send the key with every request:

```http theme={null}
Authorization: Bearer YOUR_API_KEY
```

Missing or invalid keys return an error response with `type: "authentication_error"`.