head to head · open source
calibre vs EpubReader
calibre has 25,927 GitHub stars, 2,693 forks, 6 open issues and last shipped today. EpubReader has 550 stars, 108 forks, 5 open issues and last shipped 5 months ago. calibre leads on adoption by 4,614% (25,927 vs 550 stars). calibre is written in Python under GPL-3.0; EpubReader is written in C# under Unlicense. calibre has attracted 10% as many forks as stars, EpubReader 20%. calibre was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (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 | EpubReader | |
|---|---|---|
| GitHub stars | ★ 26K | ★ 550 |
| License | GPL-3.0 | Unlicense |
| Written in | Python | C# |
| Last push | 2026-09-18 | 2026-04-18 |
| Forks | ⑂ 2.7K | ⑂ 108 |
| 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 EpubReader if
- You want the EpubReader feature set and don't need the biggest community
- You prefer the Unlicense license terms
- Your stack matches C#
- You evaluated both and EpubReader fits your workflow better
About calibre
calibre is the official source code repository for the calibre e book manager, an open source application written in Python and released under GPL 3.0. It lives in the content and publishing ecosystem as a desktop tool for books, and it is cross platform, running on Linux, Windows and macOS. The project has been hosted on GitHub for roughly thirteen years, carries about 25,900 stars and 2,683 forks, and its home on the web is calibre ebook.com, where an About page and a screenshots page document it further.
read the full calibre overview →
About EpubReader
.NET library for reading EPUB files. Supported EPUB standards: EPUB 2 (2.0, 2.0.1) EPUB 3 (3.0, 3.0.1, 3.1, 3.2, 3.3) Supported runtimes: .NET Standard = 1.3 (includes .NET Core = 1.0 and .NET = 5) .NET Framework = 4.6 Download Documentation WPF & .NET 10 console demo apps EpubReader in a nutshell Demo apps Download WPF demo app (WpfDemo.zip) This .NET Framework application demonstrates how to open EPUB books and extract their content using the library. HTML renderer used in this demo app may have difficulties while rendering content for some of the books if the HTML structure is too complicated. Download .NET 10…
read the full EpubReader overview →
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Frequently asked questions
Is calibre or EpubReader more popular?
calibre has 25,927 GitHub stars and EpubReader has 550. calibre has the larger community by that measure.
Are calibre and EpubReader free?
Both are open source. calibre is licensed under GPL-3.0 and EpubReader under Unlicense. Neither carries a licence fee.
What is the difference between calibre and EpubReader?
calibre is written in Python and EpubReader in C#. 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 EpubReader?
Choose calibre if you want the larger community (25,927 stars) or its GPL-3.0 licence terms. Choose EpubReader if its feature set, stack or Unlicense licence fits better. Both are self-hostable.