head to head · open source
calibre vs hammer-editor
calibre has 26,327 GitHub stars, 2,743 forks, 6 open issues and last shipped yesterday. hammer-editor has 811 stars, 46 forks, 54 open issues and last shipped yesterday. calibre leads on adoption by 3,146% (26,327 vs 811 stars). calibre is written in Python under GPL-3.0; hammer-editor is written in Kotlin under MIT. calibre has attracted 10% as many forks as stars, hammer-editor 6%. hammer-editor 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
| calibre | hammer-editor | |
|---|---|---|
| GitHub stars | ★ 26K | ★ 811 |
| License | GPL-3.0 | MIT |
| Written in | Python | Kotlin |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 2.7K | ⑂ 46 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick calibre if
- You weight community size — 26K stars and counting
- You want the GPL-3.0 license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick hammer-editor if
- You want the hammer-editor feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches Kotlin
- You evaluated both and hammer-editor fits your workflow better
About calibre
calibre calibre is an e book manager. It can view, convert, edit and catalog e books in all of the major e book formats. It can also talk to e book reader devices. It can go out to the internet and fetch metadata for your books. It can download newspapers and convert them into e books for convenient reading. It is cross platform, running on Linux, Windows and macOS. For more information, see the calibre About page. Screenshots Screenshots page Usage See the User Manual. Development Setting up a development environment for calibre. A tarball of the source code for the current calibre release. Bugs Bug reports and…
read the full calibre overview →
About hammer-editor
Hammer: A story editor A simple tool for building stories. ![badge kotlin] ![badge platform android] ![badge platform ios] ![badge platform windows] ![badge platform linux] ![badge platform macos] Available on: Windows [ or its GPL-3.0 licence terms. Choose hammer-editor if its feature set, stack or MIT licence fits better. Both are self-hostable.