# Spaces

A group’s data, kept on its members’ devices and synced between them. The backend you’d otherwise build, once per group.

## What it enables

- A team workspace, a club, a household or a chat for two, each with data of its own
- Invite links, and members who leave with their own copy
- Reach someone you don’t share a space with yet, through their inbox
- Contacts that work across every app

## In this section

- [Spaces](https://minca.dev/spaces/spaces.md): A space is a shared place: the records in it, and the people who may read and write them. On this page we'll make a space, invite someone to it, and then look at how a space decides who may do what.
- [Contacts](https://minca.dev/spaces/contacts.md): A contact is someone you share a private space for two with. Use this page to ask someone you already share a space with to become a contact. For someone you share no space with, use their inbox.
- [The inbox](https://minca.dev/spaces/inbox.md): An inbox is an address you hand out on purpose, so that someone you share no space with can ask to become your contact. They knock, you accept, and you both end up in a private space for two.
- [Warrants](https://minca.dev/spaces/warrants.md): A warrant (std.warrant) is proof that an account's key signed something every peer refuses and no honest app would sign. Your app uses warrants to show the members of a space that someone broke…