JLPT Reader — Privacy Policy

Last updated: August 2026

JLPT Reader is a Chrome extension that highlights Japanese vocabulary on webpages by JLPT difficulty level, shows readings and meanings on hover, and lets you save words to a personal review list. This page explains what data the extension touches and what it does with it.

Summary

Everything this extension stores stays on your device (or syncs only through your own Google account, for Chrome's built-in settings sync — never through a server we operate). We don't run any servers of our own, collect analytics, track your browsing, or share any data with third parties. There is no account to create and nothing is transmitted off your device by this extension.

What data is stored, and where

• Your settings (on/off, JLPT level, highlight density) are stored using Chrome's storage.sync API — the same mechanism Chrome uses for its own settings sync. This data is synced only through your own Google account and is never sent to us.
• Words you save (the word, its reading, meaning, JLPT level, part of speech, the example sentence it came from, the source page's title and URL, and a timestamp) are stored using Chrome's storage.local API, kept only on your device. You can delete individual saved words or clear the whole list at any time from the extension's side panel.

Neither of these ever leaves your browser through any action this extension takes. There is no external server this extension talks to.

How webpage text is used

To find and highlight Japanese vocabulary, the extension reads the visible text of the pages you browse to. This happens entirely on your device, using a dictionary and tokenizer bundled inside the extension itself — page text is never transmitted anywhere, logged, or stored beyond what's needed to render highlights on that page.

Why each permission is needed

• storage — to save your settings and your saved-word list, as described above.
• sidePanel — to show your saved-word list in Chrome's side panel.
• activeTab / tabs — used only when you click a saved word in the side panel, to find the browser tab showing that word's source page (if it's still open) and scroll to it. Not used for browsing history or any other purpose.
• offscreen — used to keep the vocabulary dictionary loaded in the background so it doesn't have to reload every time you visit a new page.
• host permission (access to page content) — needed so the extension can read a page's visible text to detect and highlight Japanese vocabulary on it, as described above.

Third-party data used to power the dictionary

The vocabulary dictionary bundled with this extension is built from JLPT vocabulary lists (Jonathan Waller / stephenmk/yomitan-jlpt-vocab) and JMdict (© EDRDG), both licensed under Creative Commons BY-SA 4.0. This is static reference data included in the extension package at build time — it is not a live connection to any external service.

Changes to this policy

If this policy changes, the "last updated" date above will change accordingly.

Contact

Questions about this policy or the extension can be filed as an issue at github.com/ak2835-creator/Yomukun/issues.