あ Subbun
Chrome extension · 100% on-device

Japanese video, in English.

Watch any Japanese video with instant English subtitles. Translation runs entirely in your browser — your content never leaves your computer.

Add to Chrome See how it works

Free on YouTube · 14-day Pro trial on every other site · No credit card required

Save six clicks per video.

YouTube's auto-translate menu is hidden behind six clicks — every video, every time. Subbun puts English subtitles on Japanese video with one click of the CC button.

Without Subbun
  1. Click CC
  2. Click gear icon
  3. Click "Subtitles/CC"
  4. Click "Auto-translate"
  5. Scroll language list
  6. Click "English"
6 clicks
…and the setting often resets between videos.
With Subbun
  1. Click CC
1 click
Once. Works on every supported site.

Live English subtitles, on every Japanese video site.

Turn on the platform's Japanese captions. Subbun reads them, translates them on-device with Chrome's built-in Gemini Nano AI, and overlays the English right under the video. No menus, no API keys, no setup.

  • ✓ 11 sites supported — including TVer, NHK Plus, and U-NEXT that YouTube auto-translate can't even reach.
  • ✓ Honorifics preserved — Tanaka-san stays Tanaka-san. Sensei stays sensei. Better than commodity MT.
  • ✓ Anime, drama, news, vlog presets tuned per content type.
  • ✓ Your glossary, your rules — pin character names and terms once, apply forever.
  • ✓ 100% on-device — subtitle text never leaves your machine. No servers, no API keys.
Add to Chrome
Demo video — drop your 30-second .mp4 here
Works on
YouTube Netflix Amazon Prime Abema Niconico Crunchyroll TVer NHK Plus U-NEXT Disney+ Hulu Japan

Simple pricing.

Free on YouTube forever. Pro unlocks every other supported site.

Free

YouTube only. Translation runs on your device.

$0 forever
  • ✓ YouTube unlimited
  • ✓ All translation engines
  • ✓ Native English subtitle overlay
  • ✓ No card required
Add to Chrome
14-day trial

Pro Monthly

Every supported site, plus presets and glossary.

$4.99 / month
  • ✓ All 11 sites unlocked
  • ✓ Anime / drama / news presets
  • ✓ Custom glossary + character names
  • ✓ Quality mode (LLM-only)
  • ✓ Cancel anytime
Start 14-day trial

Lifetime

Pay once, use forever. Best value for regular viewers.

$59 once
  • ✓ Everything in Pro
  • ✓ All future features
  • ✓ All future site additions
  • ✓ 60-day refund
Get Lifetime

Common questions

More on the help page.

Is translation really on-device? Where does my data go? +
Yes. Subbun uses Chrome's built-in AI (Gemini Nano + Translator API), which runs in your browser process. Subtitle text never leaves your computer. The only thing we send to our servers is an anonymous license instance ID for Pro validation, and you can opt out of usage stats entirely.
What Chrome version do I need? +
Chrome 138 or newer on desktop (Windows, macOS 13+, Linux, ChromeOS). Chrome for Android/iOS doesn't expose the on-device AI APIs yet, so the extension can't work there.
Will it work on Netflix / Crunchyroll / [specific site]? +
Currently supported: YouTube, Netflix, Amazon Prime, Abema, Niconico, Crunchyroll, TVer, NHK Plus, U-NEXT, Disney+, and Hulu Japan. Each site needs to expose subtitles in DOM (we don't transcribe audio). If your favorite JP site isn't on the list, email us and we'll prioritize it.
Why isn't it free forever? +
YouTube is free forever. We charge for the other sites because each one is ongoing engineering effort — sites change their player DOM regularly and we ship patches. The subscription funds the maintenance.
Can I cancel? Is there a refund? +
Yes to both. Monthly cancellations take effect at the end of the billing cycle. Lemon Squeezy (our merchant of record) offers a no-questions 60-day refund on lifetime and annual purchases.
Does it work outside Japan / with VPN? +
Yes. Subbun runs entirely in your browser — there's no geo-restriction on our side. Some Japanese streaming sites (TVer, NHK Plus, U-NEXT) are themselves geo-restricted to Japan; using a VPN is between you and them.

Watch Japanese the easy way.

Free on YouTube. 14-day Pro trial on everything else. Install in 30 seconds.

Add to Chrome