On stage now, @django — arguing for widespread adoption of ActivityPub client-server (C2S) protocol.

[reiver@mastodon.social]

On stage now, @django — arguing for widespread adoption of ActivityPub client-server (C2S) protocol.

I agree with him.

At the very least, to make extension of ActivityPub through JSON-LD namespaces possible.

But also to decouple Fediverse client development from Fediverse server development.

And more.

#ActivityPub #FediDev #FediDevs #Fediverse #FOSDEM #FOSDEM2026 #SocialWeb #SocialWebFOSDEM #SocialWebFOSDEM2026

[toddsundsted@epiktistes.com]

@reiver I’d love to see this but is it feasible without mastodon on board?

[julian@activitypub.space]

@toddsundsted@epiktistes.com absolutely.

In fact, the app that made the AP news rounds a couple months ago was Holos, an AP client on your phone that connected to a server elsewhere. That's the ideal use case for C2S, but alas they didn't go that route.

I'm hoping to look into using it to enable cross-instance activities. Think "liking and replying" using your Mastodon account while browsing a WordPress site.

[toddsundsted@epiktistes.com]

@julian @reiver i think i saw that thread a while ago and thought it was pretty clever.

[mcc@mastodon.social]

@reiver @toddsundsted Which server softwares *do* support it exactly?

[julian@activitypub.space]

@mcc@mastodon.social hmm...

Mitra from @silverpill@mitra.social and OMI by @mariusor@metalhead.club come to mind, but unsure of any more.

[mariusor@metalhead.club]

@julian it' ONI. :D

And yes, it's basically a JavaScript interface using client to server ActivityPub to communicate with its backend. Also in the GoActivityPub family there's another server supporting C2S called FedBOX, but this one has no frontends, is just a purely ActivityPub server.

@mcc @silverpill

[mariusor@metalhead.club]

Also to reply to @reiver 's original question the GoActivityPub library that I work does not easily support JSON-LD extensions, but that's one of the main goals I'm striving towards in this year.

There will still be limitations at the end, Go being a statically typed language, so the extensibility will most likely need to be decided at compile time - similar to using protobuf - where you generate types based on the JSON-LD context(s) that you want to support as a developer.

@julian @mcc @silverpill

[aslakr@mastodon.social]

@julian @mcc @silverpill @mariusor There is also maybe Mike Macgirvin's Forte https://codeberg.org/fortified/forte/src/branch/dev/FEDERATION.md#c2s ?