Mobilizon

Mobilizon is free and open source software for organizing groups and planning events that was launched in October 2020. It is developed by the French group Framasoft and is supposed to replace sites like Facebook, Meetup, or Eventbrite.
History.
On May 14 2019, Framasoft started its fundraising campaign for Mobilizon. It ended successfully on July 10 2019, and had its first test release on October 15 2019. The first version was released on October 27 2020, and updated to version 1.02 on November 17 2020. Mobilizon's Android app was made by the same developer who made Fedilab.
By January 2021, there were over sixty servers running Mobilizon.
Technology.
Mobilizon is written in the programing language Elixir and its web framework Phoenix. Its user interface is written in VueJS. It uses ActivityPub to share information with other federated software like Mastodon and Peertube. Most of its federation code comes from the microblogging software Pleroma.