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

# Authentication

> Authenticate API requests using Bearer tokens.

All API requests require a Bearer token in the `Authorization` header.

```text theme={null}
Authorization: Bearer un_your_api_key
```

## Getting Your Send Mail Token

Your Send Mail Token is provided when you're onboarded. Each token is unique to your account. If you need a new token, [contact us](https://unosend.co/contact).

<Note>
  Keep your token secure. Never expose it in client-side code.
</Note>

## Using the Key

Include it in every request:

```bash theme={null}
curl -X POST https://api.unosend.co/emails \
  -H "Authorization: Bearer un_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{"from": "hi@yourdomain.com", "to": ["user@example.com"], "subject": "Test", "html": "<p>Hello</p>"}'
```

## Security Best Practices

* **Never expose keys in client-side code** — only use them server-side
* **Use environment variables** — store keys in `UNOSEND_API_KEY`, not in source code
* **Rotate keys regularly** — contact us if you need to regenerate your token
* **One key per service** — request separate tokens for different apps so you can revoke independently

## Error Responses

| Status | Meaning                                     |
| ------ | ------------------------------------------- |
| `401`  | Missing or invalid API key                  |
| `403`  | Key doesn't have permission for this action |