Install the desktop app first. The extension carries no dictionary of its own: lookup and audio both come from Tomoshi running on your machine (over 127.0.0.1, never through a server). Just keep it running while you use the extension — minimised is fine. Not installed yet?Download Tomoshi.

Safari (macOS)

The Safari build is not in a store — it installs together with the macOS desktop app, so if you have Tomoshi you already have it and there is nothing extra to download. Safari does insist that you turn it on yourself, which takes the three steps below.

  1. Tick Tomoshi in Safari settings

    Open Safari → menu bar Safari → Settings… → the Extensions tab → tick Tomoshi in the list.

    The Extensions tab of Safari settings, with Tomoshi ticked in the list on the left

    Not there at all? Launch the Tomoshi desktop app once, then quit and reopen Safari: the extension arrives with the app, and Safari only lists it after a rescan.

  2. Allow it to read web pages

    Once ticked, a Tomoshi icon appears in the Safari toolbar with an orange exclamation mark — that means it has not been granted access yet:

    The Tomoshi icon in the Safari toolbar, with an orange exclamation mark meaning access has not been granted

    Click it and Safari asks how much access to grant. The three options differ:

    • Always Allow on Every Website — the least fuss; select-to-look-up then works on any page. Safari asks you to confirm once more.
    • Always Allow on This Website — more conservative, but you have to grant access again on every new site.
    • Allow for One Day — a trial run; you grant access again the next day.
    The Safari extension permission dialog, with buttons for Allow for One Day, Always Allow on This Website and Always Allow on Every WebsiteThe Safari confirmation dialog shown after choosing Always Allow on Every Website

    Choosing “Always Allow on Every Website” brings up one more confirmation (right); click the button of the same name.

    The line about “passwords, phone numbers and credit cards” in that dialog is Safari’s blanket warning for every extension, not something specific to Tomoshi. The Tomoshi extension only reads the text you select yourself, and only sends it to the Tomoshi app running on your own machine (127.0.0.1) — never through a server. Its source is open under AGPL-3.0 and can be audited; see the privacy policy.

  3. Select Japanese, hold Alt

    Select a Japanese word or sentence on any page and hold ⌥ Alt to bring up the definition, pitch accent and audio; release to close. The trigger key can be changed in the extension’s settings.

    Lookup and audio both come from the Tomoshi desktop app on your machine, so keep it running while you use the extension (minimised or in the menu bar is fine). Audio is played by the desktop app, which is why muting the browser tab has no effect on it.

Safari on iPhone and iPad is not supported: the extension depends on the desktop app running locally, and there is no desktop app on mobile.

Using Chrome or Edge?

Those two live in their own stores — install from there and none of the steps above apply.

ChromeAlso works in Brave, Vivaldi and other Chromium browsersOpen in Chrome Web Store →EdgeMicrosoft Edge Add-onsOpen in Edge Add-ons →