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

# Fundamentals

- [Federations](https://docs.hubble.vote/fundamentals/federations.md): Establishes data ownership and serves as the primary vehicle for billing
- [Universes](https://docs.hubble.vote/fundamentals/universes.md)
- [Multiverses](https://docs.hubble.vote/fundamentals/multiverses.md): Sharing data between Universes