FontARA is a cross-browser WebExtension for applying your preferred fonts across the web. It supports multilingual pages through built-in, system, Google, and custom fonts, with special support for RTL-first workflows: smart RTL text detection, editable-field auto-direction, and curated per-site RTL handling.

• Install
• What Changes After Install
• User Features
• Preview
• Built-in Site Optimizations
• Browser Support
• Development Quick Start
• Architecture at a Glance
• Privacy and Permissions
• Troubleshooting
• Known Limitations
• Quality
• Roadmap
• Documentation
• Changelog
• Contributing
• Contributors
• Sponsors

Most users should install FontARA from the browser store. Local release builds are mainly for testers, reviewers, and contributors.

• Font replacement across the web through built-in, system, Google, and custom font sources.
• Works on normal websites the user enables, with built-in optimized support for AI tools, search, social, productivity, and publishing sites such as ChatGPT, Claude, Gemini, Copilot, Perplexity, Google, YouTube, Gmail, X, LinkedIn, Instagram, Facebook, GitHub, Telegram, Slack, Trello, Wikipedia, DuckDuckGo, Medium, Goodreads, Dropbox, and more.
• Per-site font and text-stroke profiles.
• Smart RTL support for right-to-left scripts, editable text surfaces, and curated site adapters.
• Custom font uploads with local-only storage.
• Backup, import, export, reset, sync settings, and cross-browser MV3 builds for Chrome, Firefox, Edge, Brave, Opera, and Safari-style packages.

• Pure WebExtension build pipeline with browser-specific MV3 targets.
• Centralized site configuration for activation, CSS fixes, profiles, and RTL.
• Unit, inject, and real-browser extension tests.
• Manual and nightly browser matrix for Chrome stable/beta and Firefox latest/beta/ESR.
• Firefox review packaging and extension lint support.

The screenshots below show the popup, options page, site controls, and browser integration.

FontARA is not limited to the sites below. The extension can apply your selected font on normal web pages you enable through global mode, include/exclude rules, the popup current-site toggle, or per-site profiles. Browser-internal pages and other restricted pages are covered under Known Limitations.

The curated list below is FontARA's built-in optimized support. It currently ships with 30 site entries, 26 bundled site CSS files, and 10 smart RTL site adapters. These sites get faster and higher-quality font application through targeted CSS injection, careful text selectors, icon/code protection, and curated RTL behavior where needed. With help from users and contributors, this optimized list can keep growing.

General font injection works across the web. Site matching, optimized CSS fixes, profiles, and RTL adapters for the built-in list are maintained in src/config and documented in docs/site-fixes.md.

FontARA is built as a pure WebExtension. Source manifests live in src/manifest*.json, runtime code is split across src/background, src/inject, src/ui, src/config, and src/utils, and the build pipeline lives in tasks.

Requirements:

• Node.js 24
• pnpm 11

pnpm install
pnpm dev

The default development command watches and rebuilds the Chrome MV3 debug extension at build/chrome-mv3-dev.

Common commands:

Popup / Options
  -> Background runtime
  -> Storage and site manager
  -> Tab notification
  -> Content script
  -> Page styles without reload

For the detailed runtime map, see docs/architecture.md.

FontARA needs broad page access because fonts are applied by a content script on the websites that the user enables. That permission allows the extension to work across the web; global, include, exclude, and per-site settings still decide where FontARA actually changes the page. The extension uses storage for settings, custom font records, site lists, backup/import data, and syncable preferences.

• Custom font files are stored locally and are excluded from sync storage.
• Runtime font loading requests only the selected Google Font CSS when Google fonts are enabled.
• Site-specific CSS is bundled with the extension and mapped through the configuration layer.
• Extension pages use a locked-down content security policy and expose only font assets to web pages.

• Browser-restricted pages such as extension stores, internal browser pages, and some privileged Mozilla domains may block content scripts.
• Cross-origin iframes depend on browser extension rules and may not expose the same runtime state as the top frame.
• Some websites ship high-churn generated selectors. FontARA protects against known brittle selector patterns, but site CSS may still need updates after a major website redesign.
• Safari-style output is generated for package compatibility work, but it is not the same as a finished Safari App Store submission.
• Google Fonts require network access to Google font endpoints when that source is selected. Bundled, system, and custom fonts do not need Google Fonts requests.

• Main CI runs lint, typecheck, unit tests, inject tests, release builds, and extension lint.
• Browser automation covers popup flows, options flows, current-site include/exclude, backup/import/reset, storage stress, Shadow DOM, iframes, SPA updates, lazy DOM, virtualized lists, and viewport rendering.
• A separate manual/nightly browser workflow runs Chrome and Firefox channel coverage.

• Generate built-in site optimization documentation directly from src/config.
• Expand real-browser coverage for more Chromium channels and Firefox ESR release gates.
• Add more curated RTL adapters and per-site profile presets.
• Improve store-release automation and screenshot freshness checks.
• Keep site CSS hygiene tests strict as new websites are added.

• Development setup
• Architecture
• Site fixes and configuration
• Testing
• Release process
• Test layers

See CHANGELOG.md for release notes, migration notes, and known release issues.

Contributions are welcome. Start with CONTRIBUTING.md before opening a pull request, especially for site fixes, browser behavior changes, and new settings.

If a website renders incorrectly, use the Site Issue template and include the exact URL, browser version, selected font, and whether the page only updates after reload.

Please also read the Code of Conduct and Security Policy.

FontARA development is sponsored by Mu.chat, a platform for building AI support and sales chatbots.

If your company uses FontARA or wants to support better typography on the web, sponsorship helps maintain browser compatibility, site fixes, testing, and release work.

The extension ships a generated Google Fonts catalog, so normal builds do not need a Google API key. To refresh that catalog from Google Fonts Developer API v1, provide the key through your shell, a CI secret, or a local gitignored .env.local file:

GOOGLE_FONTS_API_KEY="your-key" pnpm generate:google-fonts

For local development, copy .env.example to .env.local and fill the key. Never commit a real Google API key. Runtime font loading uses the public CSS2 endpoint for the selected font only.

Thank you to Saber Rastikerdar, Saleh Suzanchi, and Amin Abedi for permission to use their fonts in this extension. Thank you also to everyone who has tested, reported issues, contributed fixes, or supported the project.

FontARA is released under the MIT License.

• FontARA on GitHub
• Project website
• Sponsor: Mu.chat
• Mostafa Alahyari on LinkedIn
• Mostafa Alahyari on X