furigana.it

Add furigana to any Japanese webpage.

A browser extension that annotates kanji with readings on demand. Right-click on any page or text and select Add furigana. Everything runs locally in your browser.

Features

• On-demand annotation of Japanese webpages or selected text
• Correct morphological parsing using kuromoji
• Proper okurigana handling — 食べる → 食(た)べる
• Selectable and copyable annotated text
• No server, no tracking, no analytics

Installation

Install from Firefox Add-ons.

Usage

On Desktop, right-click and select Add furigana to annotate the entire page. To annotate a specific passage, select the text first, then right-click and choose Add furigana to selection.

On Android, open the menu (⋮), go to Extensions, then tap Add furigana.

Privacy

This extension does not collect, store, or transmit any data — see the PRIVACY.md file for details.

Development

1. Clone this repository
2. Open Firefox and navigate to about:debugging
3. Click This Firefox → Load Temporary Add-on
4. Select manifest.json

To apply changes during development:

1. After editing any file, navigate to about:debugging
2. Click This Firefox → Reload on the extension

Validate the extension against Firefox's add-on policies using web-ext:

web-ext lint

Build a .zip in dist/ ready for submission to Firefox Add-ons:

web-ext build --source-dir . --artifacts-dir ./dist --ignore-files "dist/**" ".git/**" ".github/**"

License

This project is licensed under the GPLv3 License — see the LICENSE file for details.