head to head · open source
calibre-web vs WritingTools
calibre-web has 18,216 GitHub stars, 1,863 forks, 409 open issues and last shipped yesterday. WritingTools has 2,455 stars, 159 forks, 79 open issues and last shipped 1 months ago. calibre-web leads on adoption by 642% (18,216 vs 2,455 stars). calibre-web is written in Fluent under GPL-3.0; WritingTools is written in Swift under GPL-3.0. calibre-web has attracted 10% as many forks as stars, WritingTools 6%. calibre-web 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-web | WritingTools | |
|---|---|---|
| GitHub stars | ★ 18K | ★ 2.5K |
| License | GPL-3.0 | GPL-3.0 |
| Written in | Fluent | Swift |
| Last push | 2026-09-19 | 2026-08-19 |
| Forks | ⑂ 1.9K | ⑂ 159 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick calibre-web if
- You weight community size — 18K stars and counting
- You want the GPL-3.0 license terms
- Your stack matches Fluent
- You value the larger contributor base for long-term maintenance
pick WritingTools if
- You want the WritingTools feature set and don't need the biggest community
- You prefer the GPL-3.0 license terms
- Your stack matches Swift
- You evaluated both and WritingTools fits your workflow better
About calibre-web
Calibre Web is a web application that provides a clean and intuitive interface for browsing, reading, and downloading eBooks from a valid Calibre database. It is a fork of the library project (calibreserver) and is licensed under the GPL v3. The project lives in the Calibre ecosystem, and it is distributed through PyPI as the calibreweb package as well as through Docker images. It has been developed for over eleven years and carries roughly 18,183 stars and 1,856 forks on GitHub.
read the full calibre-web overview →
About WritingTools
WritingTools is an open source, system wide writing assistant for Windows, Linux, and macOS. It is inspired by Apple Intelligence Writing Tools and uses cloud based or local large language models to proofread, rewrite, summarize, and transform selected text across applications. The project is written in Swift and released under the GPL 3.0 license. The README states it works in nearly any language.
read the full WritingTools overview →
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Frequently asked questions
Is calibre-web or WritingTools more popular?
calibre-web has 18,216 GitHub stars and WritingTools has 2,455. calibre-web has the larger community by that measure.
Are calibre-web and WritingTools free?
Both are open source. calibre-web is licensed under GPL-3.0 and WritingTools under GPL-3.0. Neither carries a licence fee.
What is the difference between calibre-web and WritingTools?
calibre-web is written in Fluent and WritingTools in Swift. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, calibre-web or WritingTools?
Choose calibre-web if you want the larger community (18,216 stars) or its GPL-3.0 licence terms. Choose WritingTools if its feature set, stack or GPL-3.0 licence fits better. Both are self-hostable.