head to head · open source
koreader vs grimmory
koreader has 30,818 GitHub stars, 2,019 forks, 1,345 open issues and last shipped yesterday. grimmory has 4,642 stars, 357 forks, 243 open issues and last shipped yesterday. koreader leads on adoption by 564% (30,818 vs 4,642 stars). koreader is written in Lua under AGPL-3.0; grimmory is written in Java under AGPL-3.0. koreader has attracted 7% as many forks as stars, grimmory 8%. koreader was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (cbz, 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
| koreader | grimmory | |
|---|---|---|
| GitHub stars | ★ 31K | ★ 4.6K |
| License | AGPL-3.0 | AGPL-3.0 |
| Written in | Lua | Java |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 2.0K | ⑂ 357 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick koreader if
- You weight community size — 31K 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 grimmory if
- You want the grimmory feature set and don't need the biggest community
- You prefer the AGPL-3.0 license terms
- Your stack matches Java
- You evaluated both and grimmory fits your workflow better
About koreader
KOReader is a document viewer primarily aimed at e ink readers. [![AGPL Licence][badge license]](COPYING) [![Latest release][badge release]][link gh releases] [![Gitter][badge gitter]][link gitter] [![Mobileread][badge mobileread]][link forum] [![Build Status][badge circleci]][link circleci] [![Coverage Status][badge coverage]][link coverage] [![Weblate Status][badge weblate]][link weblate] Download • User guide • Wiki • Developer docs Main features portable : runs on embedded devices (Cervantes, Kindle, Kobo, PocketBook, reMarkable), Android and Linux computers. Developers can run a KOReader emulator in Linux…
read the full koreader overview →
About grimmory
Grimmory is a self hosted digital library for people who take their reading seriously. Documentation · Quick Start · Translations · Discord · Releases Features Supported Formats Quick Start [!TIP] For OIDC setup, advanced configuration, or upgrade guides, see the full documentation. Requirements: Docker and Docker Compose. Image Repositories Step 1: Environment Configuration Create a .env file: Step 2: Docker Compose Stable images are published from semantic release tags on main as vX.Y.Z plus latest . Nightly images are built from develop and tagged nightly . Create a docker compose.yml or copy and adapt…
read the full grimmory overview →
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Frequently asked questions
Is koreader or grimmory more popular?
koreader has 30,818 GitHub stars and grimmory has 4,642. koreader has the larger community by that measure.
Are koreader and grimmory free?
Both are open source. koreader is licensed under AGPL-3.0 and grimmory under AGPL-3.0. Neither carries a licence fee.
What is the difference between koreader and grimmory?
koreader is written in Lua and grimmory in Java. 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 grimmory?
Choose koreader if you want the larger community (30,818 stars) or its AGPL-3.0 licence terms. Choose grimmory if its feature set, stack or AGPL-3.0 licence fits better. Both are self-hostable.