The federated universe (fediverse) is growing at a steady rate, and this is good. However, just like other software that are based on an open standard protocol, ActivityPub-based software needs a tool that validates its implementation to ensure its level of compatibility with the rest.

At the moment, I use Micro.blog, Mastodon, PixelFed and CalcKey/MissKey. Mastodon users can follow and interact with the other three, Micro.blog, PixelFed and CalcKey/MissKey. Unfortunately, for some reason, whilst PixelFed can see Micro.blog users, it can’t see Micro.blog posts with photos (in contrast, PixelFed can see Mastodon posts with photos). CalcKey/MissKey is even worse as it cannot even see Micro.blog accounts! Micro.blog can see PixelFed and CalcKey/MissKey users, but not posts/photos. Weird, huh?

I am not sure where the issue lies - Micro.blog, PixelFed or MissKey? Hence, the need for an interoperability validation tool.