head to head · open source
koodo-reader vs substance
koodo-reader has 28,699 GitHub stars, 2,148 forks, 271 open issues and last shipped 2 days ago. substance has 2,738 stars, 121 forks, 41 open issues and last shipped 7 months ago. koodo-reader leads on adoption by 948% (28,699 vs 2,738 stars). koodo-reader is written in JavaScript under AGPL-3.0; substance is written in JavaScript under MIT. koodo-reader has attracted 7% as many forks as stars, substance 4%. koodo-reader was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (html), 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
| koodo-reader | substance | |
|---|---|---|
| GitHub stars | ★ 29K | ★ 2.7K |
| License | AGPL-3.0 | MIT |
| Written in | JavaScript | JavaScript |
| Last push | 2026-11-01 | 2026-04-02 |
| Forks | ⑂ 2.1K | ⑂ 121 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick koodo-reader if
- You weight community size — 29K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches JavaScript
- You value the larger contributor base for long-term maintenance
pick substance if
- You want the substance feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches JavaScript
- You evaluated both and substance fits your workflow better
About koodo-reader
简体中文 हिंदी Português Indonesian English Türkçe Koodo Reader A cross platform ebook reader Download Preview Roadmap Document Plugins Preview Features Format support: EPUB ( .epub ) PDF ( .pdf ) DRM free Mobipocket ( .mobi ) and Kindle ( .azw3 , .azw ) Plain text ( .txt ) FictionBook ( .fb2 ) Comic book archive ( .cbr , .cbz , .cbt , .cb7 ) Rich text ( .md , .docx ) HyperText ( .html , .xml , .xhtml , .mhtml , .htm ) Platform support: Windows , macOS , Linux , Android , iOS and Web Sync and backup your data with OneDrive , Google Drive , Dropbox , iCloud , MEGA , pCloud , Yandex Disk , Box , FTP , SFTP , WebDAV…
read the full koodo-reader overview →
About substance
Substance.js Substance is a JavaScript library for web based content editing. It provides building blocks for realizing custom text editors and web based publishing system. It is developed to power our online editing platform Substance. Development Install the dev dependencies. Run the dev server. Navigate to for the running the browser test suite. The test suite is rebuilt as you make changes to the source files. To run the test suite headless.
read the full substance overview →
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Frequently asked questions
Is koodo-reader or substance more popular?
koodo-reader has 28,699 GitHub stars and substance has 2,738. koodo-reader has the larger community by that measure.
Are koodo-reader and substance free?
Both are open source. koodo-reader is licensed under AGPL-3.0 and substance under MIT. Neither carries a licence fee.
What is the difference between koodo-reader and substance?
koodo-reader is written in JavaScript and substance 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, koodo-reader or substance?
Choose koodo-reader if you want the larger community (28,699 stars) or its AGPL-3.0 licence terms. Choose substance if its feature set, stack or MIT licence fits better. Both are self-hostable.