Simon Willison’s Weblog


8 items tagged “activitypub”


Threads has entered the fediverse (via) Threads users with public profiles in certain countries can now turn on a setting which makes their posts available in the fediverse—so users of ActivityPub systems such as Mastodon can follow their accounts to subscribe to their posts.

It’s only a partial integration at the moment: Threads users can’t themselves follow accounts from other providers yet, and their notifications will show them likes but not boosts or replies: “For now, people who want to see replies on their posts on other fediverse servers will have to visit those servers directly.”

Depending on how you count, Mastodon has around 9m user accounts of which 1m are active. Threads claims more than 130m active monthly users. The Threads team are developing these features cautiously which is reassuring to see—a clumsy or thoughtless integration could cause all sorts of damage just from the sheer scale of their service. # 22nd March 2024, 8:15 pm

ActivityPub Server in a Single PHP File (via) Terence Eden: “Any computer program can be designed to run from a single file if you architect it wrong enough!”

I love this as a clear, easy-to-follow example of the core implementation details of the ActivityPub protocol—and a reminder that often a single PHP file is all you need. # 19th February 2024, 12:20 am


Basically, we’re in the process of replacing our whole social back-end with ActivityPub. I think Flipboard is going to be the first mainstream consumer service that existed in a walled garden that switches over to ActivityPub.

Mike McCue, CEO of Flipboard # 18th December 2023, 6:45 pm

Wildebeest (via) New project from Cloudflare, first quietly unveiled three weeks ago: “Wildebeest is an ActivityPub and Mastodon-compatible server”. It’s built using a flurry of Cloudflare-specific technology, including Workers, Pages and their SQLite-based D1 database. # 23rd January 2023, 12:03 am


Playing with ActivityPub (via) Tom MacWright describes his attempts to build the simplest possible ActivityPub publication—for a static site powered by Jekyll, where he used Netlify functions to handle incoming subscriptions (storing them in PlanetScale via their Deno API library) and wrote a script which loops through and notifies all of his subscriptions every time he publishes something new. # 10th December 2022, 12:58 am

Understanding a Protocol. Andrew’s latest notes on how ActivityPub and Mastodon work under the hood, based on his extensive development work building out Takahē. # 6th December 2022, 12:50 am

... it [ActivityPub] is crucially good enough. Perfect is the enemy of good, and in ActivityPub we have a protocol that has flaws but, crucially, that works, and has a standard we can all mostly agree on how to implement—and eventually, I hope, agree on how to improve.

Andrew Godwin # 19th November 2022, 4:02 pm

Mastodon is just blogs

And that’s great. It’s also the return of Google Reader!

[... 1560 words]