Mastodon

Mastodon is a large social media network built as a decentralized federation of independently operated servers. It has a strong focus on privacy and anti-abuse features. Mastodon's server-side technology is Ruby on Rails, and its front end is written in JavaScript (React.js and Redux). It implements both the OStatus and ActivityPub protocols and is thus interoperable with other social networks. There are several client applications for different platforms available.