PubKit Officially Launches Closed Beta
wedistribute.org
PubKit is a spinoff project from Pixelfed, and is used by the project's lead developer to actually develop Pixelfed. It has some pretty great ideas about mocking up entities and data, testing data streams, and working with different server implementations to see where pieces might differ.
Dansup puts in some tremendous work for the fediverse. Hats off to him. I hope he's not stretching himself too thin though.
At least he seems to be enjoying it, embracing the creative process and developing whatever he's interested in. Seems like a pretty healthy approach.