Thanks for this awesome project to create an app supporting both IndieWeb and fediverse servers.
Although the Mastodon API is currently the most common way for a client app to connect with server software federating over ActivityPub, it isn't the the client-to-server API defined in the ActivityPub spec. A couple of server projects have implemented the AP C2S API to some extent, including Epicycon and Streams, and a few others are experimenting with it. It would be great to have a few more apps implement it too, so the interactions between those servers and apps over the AP C2S API can be tested.
Does IndiePass support the ActivityPub client-to-server API? If not, would you be willing to give it a go?