head to head · open source
koreader vs PolyglotPDF
koreader has 29,761 GitHub stars, 1,908 forks, 1,345 open issues and last shipped yesterday. PolyglotPDF has 1,321 stars, 198 forks, 14 open issues and last shipped 12 months ago. koreader leads on adoption by 2,153% (29,761 vs 1,321 stars). koreader is written in Lua under AGPL-3.0; PolyglotPDF is written in Python under GPL-3.0. koreader has attracted 6% as many forks as stars, PolyglotPDF 15%. koreader was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (ebook), 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
| koreader | PolyglotPDF | |
|---|---|---|
| GitHub stars | ★ 30K | ★ 1.3K |
| License | AGPL-3.0 | GPL-3.0 |
| Written in | Lua | Python |
| Last push | 2026-09-17 | 2025-09-28 |
| Forks | ⑂ 1.9K | ⑂ 198 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick koreader if
- You weight community size — 30K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches Lua
- You value the larger contributor base for long-term maintenance
pick PolyglotPDF if
- You want the PolyglotPDF feature set and don't need the biggest community
- You prefer the GPL-3.0 license terms
- Your stack matches Python
- You evaluated both and PolyglotPDF fits your workflow better
About koreader
KOReader is a free, AGPL 3.0 licensed document viewer written in Lua that runs on e ink readers from Cervantes, Kindle, Kobo and PocketBook, on reMarkable, and on Android and desktop Linux, aimed at readers who want broader format support, finer typesetting control and better performance than the reading software shipped with their device.
read the full koreader overview →
About PolyglotPDF
PolyglotPDF is a Python based multilingual eBook and PDF processing tool for translating documents while preserving original layout. It targets scanned and digital PDFs, and it sits in the content publishing ecosystem as an open source layout preserving translator. The README describes specialized techniques for recognizing text, tables, and formulas in PDF documents, with processing typically completed within one second and full document translations usually completed within ten seconds depending on the translation API provider.
read the full PolyglotPDF overview →
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Frequently asked questions
Is koreader or PolyglotPDF more popular?
koreader has 29,761 GitHub stars and PolyglotPDF has 1,321. koreader has the larger community by that measure.
Are koreader and PolyglotPDF free?
Both are open source. koreader is licensed under AGPL-3.0 and PolyglotPDF under GPL-3.0. Neither carries a licence fee.
What is the difference between koreader and PolyglotPDF?
koreader is written in Lua and PolyglotPDF in Python. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, koreader or PolyglotPDF?
Choose koreader if you want the larger community (29,761 stars) or its AGPL-3.0 licence terms. Choose PolyglotPDF if its feature set, stack or GPL-3.0 licence fits better. Both are self-hostable.