[synchronise]

For what it's worth, Hubzilla is working on getting an ActivityPub API up soon.

They're also looking to implement OpenID2 so it can be used to log into websites just like Facebook currently can.

[zotlabs]

ActivityPub has been supported in Hubzilla since around June/July 2017. It provides social communications in ActivityPub, Diaspora, OStatus, and Zot. It's designed primarily as a distributed content management and decentralised identity/privacy platform, whereas most of the other fediverse projects focus primarily on social networking.