> For the complete documentation index, see [llms.txt](https://fmtc.jaffaketchup.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://fmtc.jaffaketchup.dev/usage/root-and-stores.md).

# Root & Stores

FMTC uses a *root* and *stores* to structure its data. In general, a single root exists (which uses a single [backend](/usage/initialisation.md#backends)), which contains multiple named stores. Cached tiles can belong to multiple stores, which reduces duplication and maximizes flexibility.

{% hint style="info" %}
The structures use the ambient backend when a method is invoked on it, not at construction time.

Therefore, it is possible to construct an `FMTCStore`/`FMTCRoot` before initialisation, but 'using' any methods on it will throw `RootUnavailable`.
{% endhint %}