Last updated: 19 July 2026

Yomu does not sell personal data and does not operate advertising or analytics trackers. Its settings, imported dictionaries, local review data, and cached lookups stay in your browser unless you deliberately export them or enable a feature that uses an external service.


The extension asks to run on websites because its core purpose is to add Japanese reading, lookup, OCR, subtitle, and mining tools to the page you are viewing. It uses activeTab for user-requested visible-tab capture, scripting to install the reader, storage for settings and local study data, and context-menu access for reader shortcuts. It does not request browsing-history access.

Firefox describes the text and images Yomu reads on a page as websiteContent. Account keys and imported sign-in tokens are authenticationInfo. Yomu declares website content as required for its reader, but account information as optional. Firefox can show that optional prompt only on an extension-owned page, so account details are added from Study → Settings. If you try from an ordinary webpage, Yomu keeps the details unsaved and points you to Study. The Bunpro page helper does not read its token in the Firefox extension; it opens Study settings so you can paste the token there. If you decline Firefox's prompt, the integration stays off.

The extension does not replace or redirect your browser's new-tab page. Study is a separate page that opens only when you choose it from Yomu's toolbar menu or visit the hosted Study page.

• Settings, shortcuts, imported API credentials, dictionary preferences, and onboarding state.
• Imported Yomitan dictionaries, offline parsing dictionaries, lookup caches, and local review progress.
• Media and OCR working data only as needed for the feature you invoke; Yomu does not upload it to a Yomu account.

Uninstalling the extension normally removes its browser-managed local data. Export settings first if you want a backup.


Core dictionary imports, local parsing, annotations, settings, and local study progress work in your browser. Yomu contacts a service only when the related feature is enabled or used:

• Jiten, JPDB, or Bunpro may receive a word, sentence, review action, and the credential you supplied when you use their lookup, mining, or review features.
• Immersion Kit and Nadeshiko may receive a search term or sentence when you request examples. Google Translate may receive subtitle or sentence text when you request a translation.
• The configured audio sources may receive a word and reading. These can include Yomu Audio, Jiten, JPDB, Bunpro's audio CDN, JapanesePod101, Wikimedia Commons, or an endpoint you add yourself.
• OCR sends an image only when you invoke or enable the selected OCR route. That can be Google Lens, Google Cloud Vision with your key, a local OCR server, or another endpoint you configure.
• Recommended dictionaries and optional kanji data are downloaded from the publisher named in the interface, such as GitHub, Hugging Face, KanjiVG, or Yomu's static site.
• AnkiConnect normally receives card or review data on your own computer. A custom proxy, LAN, or Tailscale address receives only the requests you configure it to handle.

Some public data requests that a website would otherwise block can pass through Yomu's narrow public relay at edge.yomureader.com or its legacy Workers address. The relay receives the same lookup, audio, or public-resource request needed for that feature. Hosting-provider server logs and each third-party service's own privacy policy may apply.

AnkiConnect normally runs on your own computer. Bunpro's imported frontend token grants review read/write access and should be treated like a password. Yomu does not bundle or transmit your credentials to a Yomu-owned account service.

Google Drive settings sync is shown only in a browser-extension build that has an approved Google OAuth client configured. When enabled and invoked, it stores a settings snapshot in the private application-data area of your own Google Drive; Yomu does not receive that file. The use of information received from Google APIs will adhere to the Chrome Web Store User Data Policy, including the Limited Use requirements.


Chrome, Firefox, and Safari extension packages contain their executable code. They do not download or execute remote JavaScript. Optional dictionaries, definitions, examples, audio, and other data are treated as data rather than executable code.


You can erase Yomu's local data from Settings → Backup & data → Reset all data, or by removing the extension and its site data. Report privacy questions or issues through the Yomu GitHub issue tracker.