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

# Fundamentals

> XBOX services fundamentals for GDK developers: identity, sandboxes, Real-Time Activity, XSAPI, game binding, service-to-service auth, and Partner Center config.

Explore fundamentals topics for XBOX game development.

## Subtopics

<CardGroup cols={2}>
  <Card title="Game binding" icon="folder-open" href="/services/xbox-services/fundamentals/game-binding/index">
    Documentation for game binding.
  </Card>

  <Card title="Identity" icon="id-card" href="/services/xbox-services/fundamentals/identity/index">
    Documentation for identity.
  </Card>

  <Card title="Portal config" icon="folder-open" href="/services/xbox-services/fundamentals/portal-config/index">
    Documentation for portal config.
  </Card>

  <Card title="Rta" icon="folder-open" href="/services/xbox-services/fundamentals/rta/index">
    Documentation for rta.
  </Card>

  <Card title="S2s auth calls" icon="id-card" href="/services/xbox-services/fundamentals/s2s-auth-calls/index">
    Documentation for s2s auth calls.
  </Card>

  <Card title="Sandboxes" icon="folder-open" href="/services/xbox-services/fundamentals/sandboxes/index">
    Documentation for sandboxes.
  </Card>

  <Card title="XBOX services API" icon="book-open" href="/services/xbox-services/fundamentals/xbox-services-api/index">
    Documentation for XBOX services API.
  </Card>
</CardGroup>

## Guides

<CardGroup cols={2}>
  <Card title="XBOX services" icon="circle-info" href="/services/xbox-services/fundamentals/live-xbl-overview">
    XBOX services are a collection of micro-services that expose features such as profile, friends and presence, stats, leaderboards,…
  </Card>
</CardGroup>

## See also

* [Community](/services/xbox-services/community/index)
* [Develop](/services/xbox-services/develop/index)
* [Multiplayer](/services/xbox-services/multiplayer/index)
* [Player data](/services/xbox-services/player-data/index)
* [Storage](/services/xbox-services/storage/index)


## Related topics

- [Featured Stats overview](/services/xbox-services/player-data/stats-leaderboards/featured-stats/live-featuredstats-overview.md)
- [PlayFab fundamentals](/services/playfab/get-started/index.md)
- [Gaming Accessibility Fundamentals learning path](/build/game-principles/accessibility/gaf-info.md)
- [PlayFab concepts](/services/playfab/get-started/concepts.md)
- [XBOX services](/services/xbox-services/index.md)