Admin on the slrpnk.net Lemmy instance.
He/Him or what ever you feel like.
XMPP: povoq@slrpnk.net
Avatar is an image of a baby octopus.
The Pixelfed developer has been teasing Lemmy compatible groups for some years now. Apparently the code already exists, but for some reason it never gets merged.
At one point last year it looked like it would finally be released soon and I even set up a Pixelfed instance on my server to test it, but then somehow they decided working on Loops and Sup. was more important.
I got so annoyed by this lack of focus on basic functionality in general and a few other things regarding it that I deleted the instance again and do not plan to bother with anything this dev puts out again. Best of luck to them though, but I have better things to do with my time…
ActivityPub is not very well suited for real-time communication, but there are some attempts like Sup.
I think the best is to integrate an existing Fedivserse instance with XMPP. We do that on our slrpnk.net instance where every member automatically has a XMPP account reachable under the same address as on the Fediverse. We also host a Movim client that does chat as well as 1:1 A/V calls (group calls are coming soon).
The goal is to promote a local market. Not much point to have a marketplace with used items from the other side of the world.
Although manual curation of the connected instances would also work for a specialist marketplace where you can only find specific types of items.
I think both use-cases make more sense than general marketplace with mostly irrelevant entries.
It’s true that Hubzilla has access permissions for files on your WebDAV folder, and those access permissions sort of federate to other Zot protocol using sites (but not the wider Fediverse), but Nextcloud also has its own inter-Nextcloud federation where you can access files on other Nextcloud instances right inside your Nextcloud.
Well, for various reasons I stopped hosting my own Hubzilla instance some years ago, but back then it absolutely had CalDAV and CardDAV. The problem was mainly that this wasn’t well exposed in the Hubzilla web-interface, other than an event calendar. But with Thunderbird and DAVx5 etc. you could connect to it and manage it just fine. The WebDAV file storage part worked fine in the web-interface as well.
Edit: these parts are not federated though AFAIK (contrary to Nextcloud which does have some kind of file-sharing federation).
I am not aware of one with direct AP integration, but I think Opengist has an RSS feed that you could use with a bot to automate posts on a Mastodon etc. account fairly easily.