Farcaster Links (Follows, and more)

What are Links?

From the specification A Link is a relationship between two users, which means if you follow somebody that’s a relation of type link.

For now there is one link type implemented. Follows. In Social Media apps following somebody is used to express that you intend to see their posts in the future. Many apps then also allow you to message each other, show notifications of your interactions (e.g. likes, comments, etc.) and generally think you are friends.

In Farcaster it can be more generalized to more then just follows. Links are a definition of any relation between users. For now it’s used to express follows, though can be extended to express more relations. How? Links are defined by type. A link type is a string. So any identifier could be used as long as it’s smaller then 8 bytes (8 characters).

What do Links mean on Farcaster? (type “follow”)

Farcaster clients (what users use to see posts e.g. Warpcast) interpret links with type follow aka “follows” as a relation between to users to show posts of the user you follow.

Some clients have reverse chronological following feeds, where they show only posts from users you follow. Some clients have a mix of following and other posts, some clients have a feed of all posts and you can filter by following (like explorers).

How to add a new link type?

One can go to github and open a pull request with their change in the hub repository (Hub = Farcaster Nodes, the code running the network). If the change is approved it goes into the protocol. Then the new link type is live.

A link could look like:

message LinkBody {
  string type = follow;
  optional uint32 displayTimestamp = 2; // If set, clients should use this as the following create time
  oneof target {
    uint64 fid = 3;
  }
}

where type “follow” means follow for example. If you now change the type to 2 and hubs are updated by your code changes to support this new type (not reject messages with type 2), then your new link type is live.

The interpretation of what it is happens at the client level, as explained here.