> For the complete documentation index, see [llms.txt](https://relationlabs.gitbook.io/protocol/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://relationlabs.gitbook.io/protocol/open-standard-api/overview.md).

# Business Interface

Aside from interfaces provided by EIP6239, we also defined various interfaces on the business layer. They are for the following purposes:

* **NameService:** store users' identity
* **Relationship** build relations
  * **Follow:** to build a peer to peer relationship between users
  * **Dao:** to build a grouping relationship involving multiple users
* **Post:** post content
  * **PublicContent:** post public content
  * **PrivacyContent:** post privacy content