Zulip, which I lead, absolutely aims to solve this problem. We provide our full Zulip Cloud Standard paid plan for free to open source projects (and various ot

Zulip, which I lead, absolutely aims to solve this problem. We provide our full Zulip Cloud Standard paid plan for free to open source projects (and various other worthy causes!). We also prioritize and build features specifically because OSS projects asked for them: https://zulip.com/for/open-source/ https://zulip.com/for/open-source/ Hundreds of open source projects, including Rust, Julia, MariaDB, and Clojure, use Zulip as their team chat platform. We often hear from large open source projects that they substantially prefer Zulip's topic-based model to the user experience in Discord or Slack, or that they found it made their open source community work. See for example these tweets from the last few weeks: * https://twitter.com/mojavelinux/status/1409702273400201217 https://twitter.com/mojavelinux/status/1409702273400201217 * https://twitter.com/ornicar/status/1412672302601457664 https://twitter.com/ornicar/status/1412672302601457664 Also in contrast with open core products like Mattermost, Zulip is proudly 100% open source software. You can learn a bit more about Zulip's open source model here: https://blog.zulip.com/2021/04/28/why-zulip-is-on-github-sponsors/ https://blog.zulip.com/2021/04/28/why-zulip-is-on-github-spo...