head to head · open source
Bluesky vs CatchUp
Bluesky has 18,364 GitHub stars, 2,872 forks, 2,400 open issues and last shipped yesterday. CatchUp has 2,107 stars, 210 forks, 31 open issues and last shipped 6 days ago. Bluesky leads on adoption by 772% (18,364 vs 2,107 stars). Bluesky is written in TypeScript under MIT; CatchUp is written in Kotlin under Apache-2.0. Bluesky has attracted 16% as many forks as stars, CatchUp 10%. Bluesky 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
| Bluesky | CatchUp | |
|---|---|---|
| GitHub stars | ★ 18K | ★ 2.1K |
| License | MIT | Apache-2.0 |
| Written in | TypeScript | Kotlin |
| Last push | 2026-11-02 | 2026-10-28 |
| Forks | ⑂ 2.9K | ⑂ 210 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Bluesky if
- You weight community size — 18K stars and counting
- You want the MIT license terms
- Your stack matches TypeScript
- 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 Bluesky
Bluesky Social App Welcome friends! This is the codebase for the Bluesky Social app. Get the app itself: Web: bsky.app iOS: App Store Android: Play Store Development Resources This is a React Native application, written in the TypeScript programming language. It builds on the atproto TypeScript packages (like @atproto/api ), which are also open source, but in a different git repository. There is a small amount of Go language source code (in ./bskyweb/ ), for a web service that returns the React Native Web application. The Build Instructions are a good place to get started with the app itself. The Authenticated…
read the full Bluesky 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 Bluesky or CatchUp more popular?
Bluesky has 18,364 GitHub stars and CatchUp has 2,107. Bluesky has the larger community by that measure.
Are Bluesky and CatchUp free?
Both are open source. Bluesky is licensed under MIT and CatchUp under Apache-2.0. Neither carries a licence fee.
What is the difference between Bluesky and CatchUp?
Bluesky is written in TypeScript 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, Bluesky or CatchUp?
Choose Bluesky if you want the larger community (18,364 stars) or its MIT licence terms. Choose CatchUp if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.