head to head · open source
Mastodon vs Lemmy
Mastodon has 50,299 GitHub stars, 7,498 forks, 4,525 open issues and last shipped yesterday. Lemmy has 14,599 stars, 966 forks, 129 open issues and last shipped 2 days ago. Mastodon leads on adoption by 245% (50,299 vs 14,599 stars). Mastodon is written in Ruby under AGPL-3.0; Lemmy is written in Rust under AGPL-3.0. Mastodon has attracted 15% as many forks as stars, Lemmy 7%. Mastodon was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (activitypub, fediverse), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| Mastodon | Lemmy | |
|---|---|---|
| GitHub stars | ★ 50K | ★ 15K |
| License | AGPL-3.0 | AGPL-3.0 |
| Written in | Ruby | Rust |
| Last push | 2026-09-17 | 2026-09-16 |
| Forks | ⑂ 7.5K | ⑂ 966 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Mastodon if
- You weight community size — 50K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches Ruby
- You value the larger contributor base for long-term maintenance
pick Lemmy if
- You want the Lemmy feature set and don't need the biggest community
- You prefer the AGPL-3.0 license terms
- Your stack matches Rust
- You evaluated both and Lemmy fits your workflow better
About Mastodon
Mastodon is a free, open source, self hosted social network server built on ActivityPub that lets anyone run a microblogging community which interoperates with the wider Fediverse, and it is aimed at individuals, communities, and organisations that want to own their social graph instead of renting it from a platform.
read the full Mastodon overview →
About Lemmy
Lemmy is a link aggregator and forum platform for the Fediverse, written in Rust and released under the AGPL 3.0 license. It supports communities where users subscribe to forums, post links and discussions, vote, and comment. Each server can operate independently while remaining federated through ActivityPub, so users on one server can interact with users and communities on other servers.
read the full Lemmy overview →
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Frequently asked questions
Is Mastodon or Lemmy more popular?
Mastodon has 50,299 GitHub stars and Lemmy has 14,599. Mastodon has the larger community by that measure.
Are Mastodon and Lemmy free?
Both are open source. Mastodon is licensed under AGPL-3.0 and Lemmy under AGPL-3.0. Neither carries a licence fee.
What is the difference between Mastodon and Lemmy?
Mastodon is written in Ruby and Lemmy in Rust. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Mastodon or Lemmy?
Choose Mastodon if you want the larger community (50,299 stars) or its AGPL-3.0 licence terms. Choose Lemmy if its feature set, stack or AGPL-3.0 licence fits better. Both are self-hostable.