head to head · open source

koreader vs hammer-editor

koreader has 30,818 GitHub stars, 2,019 forks, 1,345 open issues and last shipped yesterday. hammer-editor has 811 stars, 46 forks, 54 open issues and last shipped yesterday. koreader leads on adoption by 3,700% (30,818 vs 811 stars). koreader is written in Lua under AGPL-3.0; hammer-editor is written in Kotlin under MIT. koreader has attracted 7% as many forks as stars, hammer-editor 6%. koreader 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.

koreader ★ 31K hammer-editor ★ 811 category Content & Publishing

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Side by side

	koreader	hammer-editor
GitHub stars	★ 31K	★ 811
License	AGPL-3.0	MIT
Written in	Lua	Kotlin
Last push	2026-11-02	2026-11-02
Forks	⑂ 2.0K	⑂ 46
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

full koreader profile →

pick hammer-editor if

You want the hammer-editor feature set and don't need the biggest community
You prefer the MIT license terms
Your stack matches Kotlin
You evaluated both and hammer-editor fits your workflow better

full hammer-editor profile →

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 hammer-editor

Hammer: A story editor A simple tool for building stories. ![badge kotlin] ![badge platform android] ![badge platform ios] ![badge platform windows] ![badge platform linux] ![badge platform macos] Available on: Windows [![.exe](

read the full hammer-editor overview →

Related comparisons

More Publishing projects

Compare either of these against the rest of the Publishing field.

koreader vs lerna koreader vs koodo-reader koreader vs calibre koreader vs readest koreader vs ebook2audiobook koreader vs calibre-web koreader vs LibreTranslate koreader vs PyMuPDF koreader vs so-novel koreader vs Calibre-Web-Automated koreader vs papermill koreader vs Weblate

Frequently asked questions

Is koreader or hammer-editor more popular?

koreader has 30,818 GitHub stars and hammer-editor has 811. koreader has the larger community by that measure.

Are koreader and hammer-editor free?

Both are open source. koreader is licensed under AGPL-3.0 and hammer-editor under MIT. Neither carries a licence fee.

What is the difference between koreader and hammer-editor?

koreader is written in Lua and hammer-editor in Kotlin. 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 hammer-editor?

Choose koreader if you want the larger community (30,818 stars) or its AGPL-3.0 licence terms. Choose hammer-editor if its feature set, stack or MIT licence fits better. Both are self-hostable.