Fedipub is an open-source Ruby library that implements ActivityPub as a pluggable engine for Ruby on Rails. Developers can add federation to an existing Rails app — or start a new one — using Rails idioms instead of a one-off protocol stack.

The library already runs in production applications to some extent. This NGI0 Commons grant improves documentation and onboarding, finishes the core ActivityPub standard, and adds common Fediverse enhancements. Source: gitlab.com/fedipub/fedipub. Run by Manyfold; project site floppy.org.uk.

Most new social apps still ship as silos because implementing ActivityPub from scratch is expensive. Fedipub lowers that cost for the Rails ecosystem, so federation is a library choice rather than a rewrite. That undercuts lock-in: users on a Fedipub-backed app can reach the rest of the Fediverse instead of starting a private graph that only one operator controls.