SubShadow
Learn Japanese as you watch
Only for iPhone
Free · In‑App Purchases
iPhone
Tap any word in the subtitles for an instant Japanese definition with furigana, then save it to a spaced-repetition deck that schedules your reviews for you.
Learn Japanese from what you're already watching.
SubShadow turns the subtitles of your own media into study material. It follows whatever is playing on your Plex or Jellyfin server — or plays video straight from your phone — and gives you a live, scrolling, tappable transcript. Tap a word you don't know and playback pauses while you read its meaning. Tap again and it resumes.
TAP TO LOOK UP
Every word in every subtitle line is tappable. An instant dictionary popover shows the meaning, the reading, and plays the pronunciation. No typing, no switching apps.
FURIGANA BUILT IN
Readings sit above the kanji right in the transcript, so you never lose the thread of a line you can almost read.
IT UNDERSTANDS CONJUGATION
Real dialogue isn't written in dictionary form. SubShadow deinflects what it sees — 遅れちゃった resolves to 遅れる — so the words people actually say are the words you can actually look up.
MINE WORDS AS YOU WATCH
One tap saves a word into your study deck along with the sentence it appeared in, so you learn it in context instead of as a bare entry on a list.
SPACED REPETITION, BUILT IN
Saved words become flashcards scheduled by FSRS, the modern algorithm behind Anki, resurfacing each one just before you'd forget it. Decks, daily limits, suspend and bury, and both flashcard and quiz review modes. No companion app needed — and any deck exports to Anki whenever you want it elsewhere.
OFFLINE DICTIONARY
The full Japanese–English dictionary ships inside the app: over 217,000 entries, tagged by JLPT level. Lookups are instant and need no internet connection at all.
BRING YOUR OWN VIDEO
• Plex and Jellyfin — browse your library and play in the app, or shadow what's already playing on your TV.
• On your phone — send files over Wi-Fi from your computer's browser, or drop them in with the Files app.
• Missing subtitles — search, download and sync them from Jimaku or OpenSubtitles without leaving the player.
TRY IT WITH NO SERVER
Choose "Try the demo" when you first open the app: a short Japanese scene runs on Now Playing as a live, tappable transcript, and the Watch tab plays the clip itself. No server, no account.
PRIVATE BY DESIGN
No accounts. No sign-up. Your words, decks and review history stay on your phone. Beyond the media server you configure, SubShadow sends only anonymous usage analytics, which you can switch off, and fetches a small configuration file at launch that carries nothing about you.
Japanese → English. iPhone.
Dictionary data: JMdict and JMnedict, property of the Electronic Dictionary Research and Development Group (EDRDG), used under the Group's licence (CC BY-SA 4.0).
Free: follow along with your TV, play the demo and videos on your phone, look up any word, and save up to 20 words. SubShadow Pro adds unlimited saved words and in-app playback of your Plex or Jellyfin library.
SubShadow Pro is available as an auto-renewable subscription or a one-time purchase:
• Pro Annual — $47.99 / year (includes a 7-day free trial)
• Pro Monthly — $9.99 / month
• Lifetime — $89.99, one-time purchase
Payment is charged to your Apple Account at confirmation of purchase. Subscriptions automatically renew unless cancelled at least 24 hours before the end of the current period; your account is charged for renewal within 24 hours prior to the end of the current period. You can manage or cancel your subscription in your Apple Account settings after purchase. Any unused portion of a free trial is forfeited when you purchase a subscription.
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://subshadow.app/privacy
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
The developer, Tomasz Macutkiewicz, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Purchases
- Usage Data
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Tomasz Macutkiewicz
- Size
- 171.8 MB
- Category
- Education
- Compatibility
Requires iOS 18.0 or later.
- iPhone
Requires iOS 18.0 or later.
- iPhone
- Languages
- English
- Age Rating
9+
- 9+
- Infrequent
Profanity or Crude Humor
Mature or Suggestive Themes
- In-App Purchases
Yes
- Pro Monthly $9.99
- Pro Annual $47.99
- SubShadow Lifetime $89.99
- Copyright
- © 2026 Tomasz Macutkiewicz