head to head · open source
calibre vs swift-toolkit
calibre has 26,327 GitHub stars, 2,743 forks, 6 open issues and last shipped yesterday. swift-toolkit has 574 stars, 262 forks, 58 open issues and last shipped yesterday. calibre leads on adoption by 4,487% (26,327 vs 574 stars). calibre is written in Python under GPL-3.0; swift-toolkit is written in Swift under BSD-3-Clause. calibre has attracted 10% as many forks as stars, swift-toolkit 46%. calibre was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (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 | swift-toolkit | |
|---|---|---|
| GitHub stars | ★ 26K | ★ 574 |
| License | GPL-3.0 | BSD-3-Clause |
| Written in | Python | Swift |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 2.7K | ⑂ 262 |
| 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 swift-toolkit if
- You want the swift-toolkit feature set and don't need the biggest community
- You prefer the BSD-3-Clause license terms
- Your stack matches Swift
- You evaluated both and swift-toolkit 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 swift-toolkit
Readium Swift Toolkit Readium Mobile is a toolkit for ebooks, audiobooks and comics written in Swift & Kotlin. [!TIP] Take a look at the guide to quickly get started. A Test App demonstrates how to integrate the Readium Swift toolkit in your own reading app. Features ✅ Implemented 🚧 Partially implemented 📆 Planned 👀 Want to do ❌ Not planned Formats Ebook and Document Formats Audiobook Formats Comic Formats Features A number of features are implemented only for some publication formats. OPDS Support DRM Support User Guides Guides are available to help you make the most of the toolkit. Publication Opening a…
read the full swift-toolkit overview →
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Frequently asked questions
Is calibre or swift-toolkit more popular?
calibre has 26,327 GitHub stars and swift-toolkit has 574. calibre has the larger community by that measure.
Are calibre and swift-toolkit free?
Both are open source. calibre is licensed under GPL-3.0 and swift-toolkit under BSD-3-Clause. Neither carries a licence fee.
What is the difference between calibre and swift-toolkit?
calibre is written in Python and swift-toolkit 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 or swift-toolkit?
Choose calibre if you want the larger community (26,327 stars) or its GPL-3.0 licence terms. Choose swift-toolkit if its feature set, stack or BSD-3-Clause licence fits better. Both are self-hostable.