🚀 Introduction

Open-Dyslexic is an open-source font designed to improve readability for readers with dyslexia. This browser extension overrides all fonts on webpages with the OpenDyslexic font and formats pages to be more easily readable.

🧩 Extensions

• Chrome
• Firefox
• Edge

🤝 Support

OpenDyslexic for Chrome is an MIT-licensed open-source project, and its ongoing development is made possible entirely by the support of these awesome backers. If you'd like to join them, please consider:

• Become a backer on GitHub
• Become a backer or sponsor on Patreon.

What's the difference between Patreon and GitHub?

Funds donated via GitHub go directly to support Robert James' full-time work on the OpenDyslexic extension.

Funds donated via Patreon will be used to compensate work and expenses for Abbie's work on the font.

Your name/logo will receive proper recognition and exposure by donating on either platform.

🙌 Contribution

Getting Started

Requires Node 22.11 or newer (the build toolchain sets this floor, and CI runs Node 22).

# Install
npm install

# Build (Chrome, into ./dist)
npm run build

# Run tests
npm run test

Build commands

# Build one browser into ./dist
npm run chrome
npm run firefox
npm run edge

# Build all three and write zips to ./build/<browser>/<version>/
npm run package

# Remove ./dist and ./build
npm run clean

# Format the codebase
npm run format

The version in the zip filename comes from the version field of the manifest in config/. Keep chrome-manifest.json, firefox-manifest.json, and edge-manifest.json on the same version when you cut a release.

🔄 Updating dependencies

# See what's behind
npm outdated

# Apply everything in range (patch + minor)
npm update

# Move a single package to its newest major
npm install --save-dev <package>@latest

After any dependency change, run the full check — the unit tests alone will not catch a broken loader or a bundling regression:

npm run test && npm run package && npm audit

All three browser builds must compile and the 75 tests must pass. The build should be completely warning-free — if webpack starts reporting asset-size hints, something real got large.

Store listing screenshots live in store/screenshots/, deliberately outside app/, so they are never bundled into the shipped zip.

Deliberate choices

Please don't "fix" these without checking the build:

• There is no Babel, and the bundle is not transpiled. Manifest V3 requires Chrome 88+, and the Firefox manifest sets strict_min_version to 114. The source only uses arrow functions, async, and spread — all supported well below those floors — so webpack ships the syntax as written. Adding babel-loader back inflated background.js from 1.4 KB to 5.5 KB with async-to-generator helpers those browsers don't need. If you ever need a lower floor, add a browserslist key rather than reintroducing a blanket ES5 transpile.
• Jest transforms with @swc/jest, not babel-jest. Its only job is turning the source's ESM into CJS, because the test files use import and the package is not "type": "module". This replaced 80 @babel/* packages with three, and cut the test run roughly in half.
• ?raw CSS imports use webpack's built-in asset/source. app/scripts/content/engine.js needs the OpenDyslexic stylesheet as a string to inject into pages. The two .css rules in webpack.config.js are split on resourceQuery so ?raw yields text while every other stylesheet goes through PostCSS. This replaced the deprecated raw-loader; keep the resourceQuery: { not: [/raw/] } guard or the raw import will be processed as a stylesheet instead.
• engines.node is >=22.11.0. The strictest dependency (webpack-cli) only needs Node 20.9, but Node 20 went end-of-life in April 2026, so the project targets 22. .github/workflows/release.yml matches this — bump both together.

The overrides block

Every entry exists to clean up Jest's own transitive tree. None of these are our direct dependencies, so the only lever is overrides. Re-run npm run test -- --coverage after touching any of them — plain npm test does not exercise test-exclude or glob.

• brace-expansion: ^5.0.8 — Jest pulls a version with two DoS advisories. npm's suggested fix is a destructive major downgrade elsewhere; this forces the patched release, which is dual-published so CommonJS consumers still work. Removing it reintroduces 19 high-severity advisories.
• test-exclude: ^7.0.1 — babel-plugin-istanbul still asks for test-exclude@^6, which drags in glob@7 and the abandoned, memory-leaking inflight. Version 7 moved to glob@^10, so this drops both.
• glob: ^13.0.6 — Jest asks for glob@^10.5.0, and that package's maintainer deprecates every trailing version, so 10 and 11 both warn on install. 13 is current and satisfies Node 22.

Together these take npm install from six deprecation warnings to one and cut about 50 packages.

Known-unfixable warning

npm install still prints one deprecation for whatwg-encoding, reached via jest-environment-jsdom → jsdom@26. It is cosmetic — npm audit stays at zero.

Do not try to fix it by overriding jsdom. jsdom@30 does drop the package, but jest-environment-jsdom pins jsdom@^26, and forcing 30 replaces it with @exodus/bytes — which is ESM-only, while html-encoding-sniffer loads it via require(). That fails every test suite with ERR_REQUIRE_ESM. The warning goes away on its own when jest-environment-jsdom bumps its own jsdom range.

Keep npm audit at zero. If a new dependency drags in advisories that its maintainer won't fix, prefer dropping the dependency over living with them — that is how the Google Translate tooling was removed.

🧪 Testing

To test, go to: chrome://extensions, enable Developer mode, and load the app as an unpacked extension.

Need more information about Chrome Extension Development? Please visit Google Chrome Extension Development.

🌍 Translations

The extension ships in 58 languages. English is the source of truth and every other locale is a translation of it.

See TRANSLATING.md for the file format and a ready-made prompt you can paste into an LLM to translate a new locale.

❓ Questions

For questions and support, please visit the GitHub issues tab.

⭐ Sponsors

📜 License

MIT Copyright (c) 2013-present