The Fediverse As Composable Distributed Applications

The promise of the Fediverse is much more than replacing Twitter

There’s an old story about someone in the dark feeling the trunk of an elephant and believing it’s a snake because they can’t see the whole animal. It’s happening again, as people switch from the Twitter crash to try to do the same thing in the Fediverse.

One of the benefits of the Fediverse is I can use the system I prefer to post things and you can follow and interact with any ActivityPub-compatible system you prefer. Your choice of, say, a photo sharing platform doesn’t dictate that I have to sign up to the same site, or even to another photo sharing thing. It’s all powered by the ActivityPub standard – which is like RSS you can reply to. But there’s the potential to end the reign of monetised surveillance (AKA advertising) with a switch to user-owned applications.

No Platform Virality

If I was posting my photos to Instagram, to follow them you would have to sign up too (and since that’s Facebook-owned, submit to all their monetised identity harvesting). But if I post with PixelFed – an ActivityPub system that is tailored to posting photographs like on Instagram – you can follow from a compatible photo tool for sure. But you can also follow – and comment – from micro-blogging systems like Mastodon or Pleroma or from video-sharing systems like PeerTube or a blogging tool like Plume.

Yes, you have to join the Fediverse somewhere, but you can do it the way that’s comfortable on a platform that shares your values and still interact with people who made different choices, and once you’ve done it you can follow any feed regardless of the platform it’s from. It’s the end of platform virality and lock-in. It means every small app can benefit from a network effect previously only available to gatekeeper platforms.

This seems to me the most important dimension of the Fediverse, and the one we need to develop. We need ActivityPub federated software tools of all kinds, cutting the link between my choices and your choices without also cutting our ability to interact with each other. I never want to have to leave my social graph behind again.

Composable Applications

This detachment goes further. I can segment my posting and use a more appropriate tool for specific content types and interaction styles. For example, I have been putting my photos while I am travelling on my new PixelFed server so that followers have the choice of following my micro-blogging feed on Mastodon, my photo feed on PixelFed or indeed both. (You can also subscribe to this blog…)

This means I don’t have to wait for my microblogging tool to get better support for posting photos; instead I can mix and match tools and build the ideal creative environment for me, and you are not affected beyond needing to follow me in more than one place. Over time this will get fixed and I will be able to offer an aggregated subscription to all my feeds - it just needs someone to write a gadget to do it!

Of course, there’s much more to it than this. Since ActivityPub has two layers, a client-to-server layer and a server-to-server layer, there is great scope for wiring composable applications together so they collaborate better. And then there’s the privacy dimension - I especially like Christine Lemmer-Webber’s OCapPub ideas. I am sure we will see much innovation both in creating user capabilities and in managing infrastructure needs. Because pretty much everything in the Fediverse is open in every sense, there is plenty of scope for relays and clients to layer fresh capabilities upon the activity stream. It’s the UNIX philosophy revisited.

Open source and standards done right

This is all powered by the dual merits of open source software and truly open standards. ActivityPub is a freely-available, royalty-free W3C standard. All the systems that manipulate it to date are open source software, which anyone can enjoy without asking permission first. Together that openness has fueled the wave of change triggered by the collapse of Twitter. But there is much more to it than that.

I’ll not tell you that calling the Fediverse “Mastodon” is a mistake (even if it is!) but I do recommend looking beyond the obvious similarities of Mastodon to Twitter and realise the phenomenon it is riding is not only bigger than a single piece of software, it’s bigger than a single category of software. Federation will get smarter and more secure new categories of activity will be added. This is not so much an elephant in the dark as a whole zoo in the dark, and we’ve only touched the first few animals.


  • Based on an original Mastodon thread
  • Header image: Tomás Saraceno’s sculpture “Stillness in Motion—Cloud Cities” seen at SF MoMA