> For the complete documentation index, see [llms.txt](https://api.circle.so/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://api.circle.so/get-started/concepts.md).

# Concepts

- [Spaces & space groups](https://api.circle.so/get-started/concepts/spaces-and-space-groups.md): Spaces are a foundational container for discussions, courses, events, chat, and image posts in Circle.
- [Posts](https://api.circle.so/get-started/concepts/posts.md): An overview of posts on Circle
- [Messages](https://api.circle.so/get-started/concepts/messages.md): Circle supports messaging via direct messages, group chat rooms, and chat spaces.
- [TipTap editor](https://api.circle.so/get-started/concepts/tiptap-editor.md)
- [File uploads](https://api.circle.so/get-started/concepts/file-uploads.md)
- [Rich Text Body](https://api.circle.so/get-started/concepts/rich-text-body.md)