> ## Documentation Index
> Fetch the complete documentation index at: https://docs.keystoneb2b.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Authentication

> How to authenticate Inventory API requests.

## Bearer token

Send your API key in the `Authorization` header:

```http theme={null}
Authorization: Bearer <api_key>
```

Keys are scoped to a single tenant. Each key only returns inventory for the brand it was issued to.

## Security requirements

<Warning>
  Store API keys on your servers only. Never ship keys to browsers, mobile apps, or public repositories.
</Warning>

* Rotate keys immediately if you suspect exposure.
* Use HTTPS for all requests (the production endpoint enforces TLS).
* The `health` action is the only call that works without a key.

## Requesting a key

Contact your Keystone account representative or email [support@keystoneb2b.io](mailto:support@keystoneb2b.io). Include your company name and the integration environment (production or staging).