head to head · open source
Mastodon vs CatchUp
Mastodon has 50,465 GitHub stars, 7,536 forks, 4,525 open issues and last shipped yesterday. CatchUp has 2,107 stars, 210 forks, 31 open issues and last shipped 6 days ago. Mastodon leads on adoption by 2,295% (50,465 vs 2,107 stars). Mastodon is written in Ruby under AGPL-3.0; CatchUp is written in Kotlin under Apache-2.0. Mastodon has attracted 15% as many forks as stars, CatchUp 10%. Mastodon 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
| Mastodon | CatchUp | |
|---|---|---|
| GitHub stars | ★ 50K | ★ 2.1K |
| License | AGPL-3.0 | Apache-2.0 |
| Written in | Ruby | Kotlin |
| Last push | 2026-11-02 | 2026-10-28 |
| Forks | ⑂ 7.5K | ⑂ 210 |
| 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 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 Mastodon
[!NOTE] Want to learn more about Mastodon? Click below to find out more in a video. Mastodon is a free, open source social network server based on ActivityPub where users can follow friends and discover new ones. On Mastodon, users can publish anything they want: links, pictures, text, and video. All Mastodon servers are interoperable as a federated network (users on one server can seamlessly communicate with users from another one, including non Mastodon software that implements ActivityPub!) Navigation Project homepage 🐘 Donate to support development 🎁 View sponsors Blog 📰 Documentation 📚 Official…
read the full Mastodon overview →
About CatchUp
CatchUp ======= An app for catching up on things. Motivations There's a lot of services I like reading up on throughout the day. Most of these services have dedicated apps for consuming them, but often times I just want to skim the front page and only deep dive occasionally. Enter CatchUp: a high level presentation of the "front page" of several services in short form, and intelligent deeplinking into dedicated apps if you want to go further. CatchUp is not an all purpose client for each of these services, just the concierge for at a glance details and router for getting on your way. It does not support login…
read the full CatchUp overview →
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Frequently asked questions
Is Mastodon or CatchUp more popular?
Mastodon has 50,465 GitHub stars and CatchUp has 2,107. Mastodon has the larger community by that measure.
Are Mastodon and CatchUp free?
Both are open source. Mastodon is licensed under AGPL-3.0 and CatchUp under Apache-2.0. Neither carries a licence fee.
What is the difference between Mastodon and CatchUp?
Mastodon is written in Ruby 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, Mastodon or CatchUp?
Choose Mastodon if you want the larger community (50,465 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.