1621.

A bare-minimum ActivityPub server from scratch

grishka.me/blog/activitypub-from-scratch

This is a translation of the article I originally wrote in Russian a year ago.
Lately, after Elon Musk bought Twitter, people have started looking for its alternatives – and many found one in Mastodon.
Mastodon is a decentralized social media platform that works on the federation model, like email. The federation protocol is called ActivityPub and is a W3C standard, and Mastodon is far from being its only implementation, albeit it is the most popular one.