head to head · open source
calibre vs vmprint
calibre has 26,327 GitHub stars, 2,743 forks, 6 open issues and last shipped yesterday. vmprint has 679 stars, 30 forks, 1 open issues and last shipped 2 months ago. calibre leads on adoption by 3,777% (26,327 vs 679 stars). calibre is written in Python under GPL-3.0; vmprint is written in JavaScript under Apache-2.0. calibre has attracted 10% as many forks as stars, vmprint 4%. calibre 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 | vmprint | |
|---|---|---|
| GitHub stars | ★ 26K | ★ 679 |
| License | GPL-3.0 | Apache-2.0 |
| Written in | Python | JavaScript |
| Last push | 2026-11-02 | 2026-08-29 |
| Forks | ⑂ 2.7K | ⑂ 30 |
| 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 vmprint if
- You want the vmprint feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches JavaScript
- You evaluated both and vmprint 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 vmprint
VMPrint I built the layout engine so you don't have to. VMPrint is a layout engine. Not a PDF library. Not a renderer. A layout engine: the component that decides where every glyph goes, negotiates page breaks, resolves mutual spatial dependencies between dynamic regions, and produces a flat array of exact X/Y coordinates for every box and text run in the document. What you do with that output is your call: render to PDF, replay on a Canvas, drive a word processor's display layer, feed it to a WebGL pipeline. The engine's job ends when the math is done. The architecture is backed by a pending patent. The core…
read the full vmprint overview →
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Frequently asked questions
Is calibre or vmprint more popular?
calibre has 26,327 GitHub stars and vmprint has 679. calibre has the larger community by that measure.
Are calibre and vmprint free?
Both are open source. calibre is licensed under GPL-3.0 and vmprint under Apache-2.0. Neither carries a licence fee.
What is the difference between calibre and vmprint?
calibre is written in Python and vmprint 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 vmprint?
Choose calibre if you want the larger community (26,327 stars) or its GPL-3.0 licence terms. Choose vmprint if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.