# Objects

PawPub has five fundamental types of "pushable object" (anything that can be sent to an instance's [push endpoint](endpoint/push)), which are:
- [Actor](objects/actor): represents an entity that can "do something"
- [Note](objects/note): represents a post, article or message of some kind
- [Interaction](objects/interaction): represents an action that can be taken on a note (e.g. like/dislike)
- [Extension](objects/extension): represents an arbitrary, extension-defined object
- [Tombstone](objects/tombstone): represents an object that previously existed but has been deleted