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

# Authentication

> The Server-to-server Conversions API requires a bearer API key.

The Server-to-server Conversions API requires a partner API key, sent as a bearer token:

```
Authorization: Bearer <YOUR_API_KEY>
```

## Getting a key

Reach out to your Thrad contact to issue an API key for your partner / advertiser account. Keep keys server-side only — never embed them in browser code or mobile binaries.

## Errors

| Status | Reason |
| - | - |
| `401 Missing bearer token` | No `Authorization` header. |
| `401 Invalid API key` | Token doesn't match any active key. |


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.