head to head · open source
Lemmy vs CatchUp
Lemmy has 14,599 GitHub stars, 966 forks, 129 open issues and last shipped 2 days ago. CatchUp has 2,101 stars, 210 forks, 31 open issues and last shipped 3 days ago. Lemmy leads on adoption by 595% (14,599 vs 2,101 stars). Lemmy is written in Rust under AGPL-3.0; CatchUp is written in Kotlin under Apache-2.0. Lemmy has attracted 7% as many forks as stars, CatchUp 10%. Lemmy was the more recently maintained of the two, and both are self-hostable with no licence fee.
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
| Lemmy | CatchUp | |
|---|---|---|
| GitHub stars | ★ 15K | ★ 2.1K |
| License | AGPL-3.0 | Apache-2.0 |
| Written in | Rust | Kotlin |
| Last push | 2026-09-16 | 2026-09-15 |
| Forks | ⑂ 966 | ⑂ 210 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Lemmy if
- You weight community size — 15K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches Rust
- You value the larger contributor base for long-term maintenance
pick CatchUp if
- You want the CatchUp feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Kotlin
- You evaluated both and CatchUp fits your workflow better
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 →
About CatchUp
CatchUp is an open source Android app written in Kotlin under the Apache 2.0 license. It sits in the Android community and social networking space and gives a short form view of several services instead of asking users to open many dedicated apps.
read the full CatchUp overview →
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Frequently asked questions
Is Lemmy or CatchUp more popular?
Lemmy has 14,599 GitHub stars and CatchUp has 2,101. Lemmy has the larger community by that measure.
Are Lemmy and CatchUp free?
Both are open source. Lemmy is licensed under AGPL-3.0 and CatchUp under Apache-2.0. Neither carries a licence fee.
What is the difference between Lemmy and CatchUp?
Lemmy is written in Rust and CatchUp in Kotlin. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Lemmy or CatchUp?
Choose Lemmy if you want the larger community (14,599 stars) or its AGPL-3.0 licence terms. Choose CatchUp if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.