Reese Ricci Armstrong

@reesericci@socialhub.activitypub.rocks · Joined ⁨Jul⁩ ⁨2026⁩

Replying to an earlier post

I'm really not sold here on adding this to the FEP when all of this is specified in the ActivityPub specification - people just don't use it when it comes to C2S. Managing collections is a core part of the spec.

I guess I see an argument for specifying that emoji catalogs should be a "well known" collection provided by the server, but isn't that the standard for collections? User-created collections aren't specified in the ActivityPub spec.

FEP-de8d: Emoji Catalogs

This FEP introduces Emoji Catalog, which provide a way for both clients and servers to publish and discover custom emoji.

ActivityPub implementations, including Mastodon, commonly support custom emoji. FEP-9098 defines how an Emoji is embedded in an Activity Streams object, but it does not define how a client discovers the emoji available for use when composing new content.

This leads to ActivityPub clients relying on implementation-specific APIs such as the Mastodon custom emoji endpoint.

A standardized emoji catalog allows a C2S client to:

  • Populate an emoji picker.
  • Determine which emoji the authenticated actor may use.
  • Retrieve emoji categories and static previews.
  • Update its local cache when the catalog changes.

Additionally, a standardized emoji catalog allows servers to publish custom emoji that other ActivityPub implementations can discover reliably.

Read full FEP at https://codeberg.org/fediverse/fep/pulls/888

Summary card of an issue titled "Add FEP-de8d: Emoji Catalogs" in repository fediverse/fepCodeberg.orgAdd FEP-de8d: Emoji CatalogsThis FEP introduces Emoji Catalog, which provide a way for both clients and servers to publish and discover custom emoji. ActivityPub implementations, including Mastodon, commonly support custom emoji. FEP-9098 defines how an Emoji is embedded in an Activity Streams object, but it does not def...