> For the complete documentation index, see [llms.txt](https://api.docs.fan/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://api.docs.fan/native-gateway/s2s.md).

# How it works

The native integration path lets your servers call the Fanatics ecosystem directly through our API **gateway**, rather than going through the hosted Web SSO site. It is the right choice for backend-to-backend access and for flows that don't involve a browser redirect.

The gateway fronts our native APIs and is reachable at a dedicated host per environment (production: `auth.apis.fan`). See [Environments & Endpoints](/reference/environments.md) for all hosts.

## Getting an access token

There are two ways to obtain an access token for the gateway:

* [**Server-to-server (client credentials)**](/native-gateway/s2s-auth.md) — your application authenticates with its `client_id` and `client_secret` to receive an access token that is **not tied to any specific user**. Use this for backend operations that act on behalf of your system.
* [**Assertions**](/assertions/point-of-sale.md) — redeem a pre-authorized, user-scoped assertion for an access token via the `jwt_bearer` grant. Use this when acting on behalf of a specific already-authenticated user without re-authenticating them.

In all cases the access token must be stored securely and never exposed outside of your system except to call our APIs.

## API reference

For the full list of gateway endpoints and schemas, see the [Gateway API Reference](/native-gateway/api-reference.md).