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

# Authentication

> Authenticate MaxAPI requests with an API key.

MaxAPI authenticates requests with API keys. Most endpoints expect a Bearer token in the `Authorization` header:

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

```bash theme={null}
curl https://api.maxapi.ai/v1/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"YOUR_MODEL_ID","messages":[{"role":"user","content":"Hello"}]}'
```

<Note>
  Some provider-native endpoints use a different authentication format. Follow the header definition on the endpoint page.
</Note>

## Protect your keys

* Store API keys in server-side environment variables or a secrets manager.
* Do not include keys in frontend code, mobile applications, or public repositories.
* Create separate keys for each application and environment.
* Revoke and replace a key immediately if you suspect exposure.

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

## Authentication errors

| Status | Cause                                                 | Resolution                                     |
| ------ | ----------------------------------------------------- | ---------------------------------------------- |
| `401`  | The API key is missing, invalid, or revoked           | Check the request header and use an active key |
| `403`  | The key cannot access the requested model or endpoint | Check the account and model permissions        |