Eugen Rochko (Russian: Евгений Рочко, romanized: Yevgeniy Rochko; born 22 January 1993[1]) is a German software developer, best known as the creator of Mastodon, a decentralized open-source social networking platform consisting of a large number of independently run nodes, known as instances, each with its own code of conduct, terms of service, privacy policy, privacy options, and moderation policies.

[7] By April 2017, there were 1,000 independently run "instances" on Mastodon's federated social network platform with "hundreds of thousands of users" using personal and public servers, according to a June 2017 Free Software Foundation (FSF) interview.

[8] In June 2017 Rochko told an interviewer that he loved free software and this, along with his growing dissatisfaction with Twitter, had also been factors in his creation of Mastodon.

Valens said that by 2019, there were two competing camps at Mastodon—the marginalized queers and "white, well-off, and male tech workers" whose views aligned with Rochko.

She described Rochko as a Benevolent Dictator For Life (BDFL)—a term given to some open source software developers who retain a final say in decisions.

[3] In a November 2019 interview with mint in the week following the influx of 26,000 new members from India who had exited Twitter for "opaque moderation policies, censoring government critics and failing to control hate speech", Rochko said that Mastodon had extended its policy of not condoning casteism" as well as "racism, sexism, homophobia or transphobia"[11] Rochko said that in contrast to Twitter, Mastodon had a "higher ratio of moderator-to-users" who monitor posts.

[18] Rochko said that the Mastodon server covenant mandating "active moderation against racism, sexism, homophobia, and transphobia" isolates any such use of the open source software.

[21] A Forbes article quoted Rochko saying he was optimistic that people who left Twitter for Mastodon would "enjoy a different kind of social media experience".

[15] Articles and interviews with Rochko about his role in Mastodon have been published in Der Tagesspiegel,[5][14] Esquire,[8] The Daily Dot, [3] Time,[13] and others.

In a 2018 podcast with Jerod Santo and Adam Stacoviak from Twitter and GitHub, Rochko described in depth the origins of Mastodon.