Skip to content, sitemap or skip to search.

Personal tools
Join now
You are here: Home Bulletins 2017 Spring Mastodon interview

Mastodon interview

by John Hsieh Contributions Published on Jul 10, 2017 12:16 PM

This past April, federated social network Mastodon exploded, rapidly gaining hundreds of thousands of users across more than a thousand instances of the platform. These instances are being run independently across personal and public servers--a benefit of a federated social network.

Recently, the FSF had an opportunity to interview Eugen Rochko. The interview was conducted over email and edited for content and clarity. To learn more about Mastodon, you can visit

Can you tell us a bit about yourself?

I am a recent graduate from Friedrich-Schiller-Universität Jena, where I studied computer science. I am German, of Jewish/Russian origin.

What inspired you to create Mastodon?

I was disappointed with Twitter, and have a love for free software.

Can you tell us a bit about the technical side of Mastodon?

It's made with Ruby and JavaScript. It uses Ruby on Rails as a framework, and React.js as well.

Who contributes and how are they organized?

Officially, the Mastodon team is just me (main developer, founder) and (project manager). Everyone else is on a volunteer basis--According to GitHub there are 323 different contributors as of 5/13/2017.1 There are only about a dozen regular contributors; most of them have been given write access2 to the repository, which allows them to authoritatively review pull requests. But only I and one other person can merge into the master branch.

How/why did you choose GNU Affero General Public License version 3 for Mastodon?

Originally I started with GPL, because I was familiar with it from other projects like Discourse, a free online discussion platform that can be used as a mailing list, online fourms, or chat rooms. It was suggested that I change to the AGPLv3 to prevent the XMPP/gTalk/WhatsApp situation, and I found that point compelling. To preserve federation, AGPLv3 was chosen.3

How does Mastodon relate to GNU social?

Mastodon is an OStatus application, just like GNU social.4 They are both part of the same network ("fediverse") based on this protocol.

What kinds of technical and/or social challenges did you experience during development?

Technical challenges have included a rush for large-scale optimization during the activity explosion5 and pinpointing bugs in a distributed networking environment. We have also been adjusting to people's expectations of how things should work.

How many Mastodon users are there today?

Today Mastodon has over 620,000 users on over 1,200 instances. These numbers are available on I do not track any other specific stats, but any time I look there are about 6,000 users accessing at the same time (this includes websockets connections of online users).


We'd like to thank Eugen for taking the time to do the interview, as well as thank the entire Mastodon team for their efforts. If you have suggestions for future interview candidates, email

1Mastodon has 3,031 commits by 335 contributors on GitHub (5/24/2017). The Patreon is supported by 727 individuals. 2Write access grants contributors a number of permissions, including the creation of repositories, the ability to review pull requests, and manage various reported issues, project boards, and team repos. 3To read more on licensing and federation: 4OStatus is a standard for distributed status updates and includes a number of protocols. Microblogging applications using the same protocol are able to talk with one another across instances and even specific software. 5Following several articles on Mastodon, user numbers went from 20,000 to 42,000 over two days.

Document Actions

The FSF is a charity with a worldwide mission to advance software freedom — learn about our history and work. is powered by:


Send your feedback on our translations and new translations of pages to