head to head · open source
calibre vs foliate-js
calibre has 26,327 GitHub stars, 2,743 forks, 6 open issues and last shipped yesterday. foliate-js has 1,146 stars, 296 forks, 61 open issues and last shipped 6 months ago. calibre leads on adoption by 2,197% (26,327 vs 1,146 stars). calibre is written in Python under GPL-3.0; foliate-js is written in JavaScript under MIT. calibre has attracted 10% as many forks as stars, foliate-js 26%. calibre was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 3 topic tags (ebook, ebook-reader, epub), 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
| calibre | foliate-js | |
|---|---|---|
| GitHub stars | ★ 26K | ★ 1.1K |
| License | GPL-3.0 | MIT |
| Written in | Python | JavaScript |
| Last push | 2026-11-02 | 2026-05-01 |
| Forks | ⑂ 2.7K | ⑂ 296 |
| 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 foliate-js if
- You want the foliate-js feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches JavaScript
- You evaluated both and foliate-js 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 foliate-js
foliate js Library for rendering e books in the browser. Features: Supports EPUB, MOBI, KF8 (AZW3), FB2, CBZ, PDF (experimental; requires PDF.js) Add support for other formats yourself by implementing the book interface Pure JavaScript Small and modular No hard dependencies Does not require loading whole file into memory Does not care about older browsers Demo The repo includes a demo viewer that can be used to open local files. To use it, serve the files with a server, and navigate to reader.html . Or visit the online demo hosted on GitHub. Note that it is very incomplete at the moment, and lacks many basic…
read the full foliate-js overview →
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Frequently asked questions
Is calibre or foliate-js more popular?
calibre has 26,327 GitHub stars and foliate-js has 1,146. calibre has the larger community by that measure.
Are calibre and foliate-js free?
Both are open source. calibre is licensed under GPL-3.0 and foliate-js under MIT. Neither carries a licence fee.
What is the difference between calibre and foliate-js?
calibre is written in Python and foliate-js in JavaScript. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, calibre or foliate-js?
Choose calibre if you want the larger community (26,327 stars) or its GPL-3.0 licence terms. Choose foliate-js if its feature set, stack or MIT licence fits better. Both are self-hostable.