> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ai21.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Authentication

All API requests must include an `Authorization` header \
with a **Bearer token** for authentication.

To authenticate:

1. Use your API key as the token.
2. Include it in the request header as shown below:

**Header format:**\
Authorization: Bearer \<your-api-key>

Replace `<your-api-key>` with your actual key.\
\
See the [Create an API Key guide](https://docs.ai21.com/docs/create-api-key) for step-by-step instructions.