I agree, standardization would be good.

It’s entirely up to the developers to collaborate and implement according to the spec though. ActivityPub wasn’t really designed with this use-case in mind, so the spec has limitations that warrant a specialized API, or extensions to the AP spec.

For example, the outbox is an OrderedCollection. This is how you would list posts in a magazine/community. However, there’s no way to sort by other metrics such as hot, top, or trending. Even Mastodon has its own REST API.