---
title: "Rootbly - AI Subtitle - Reviews, Revenue and Downloads in Japan | Apple App Store"
description: "Watch foreign YouTube videos with translated subtitles.  RootblySub auto-translates YouTube subtitles into your language. Just paste a URL, and AI generates subtitles you can watch instantly in our bu"
---

# Rootbly - AI Subtitle — Japan

![Rootbly App Icon](https://is1-ssl.mzstatic.com/image/thumb/Purple221/v4/9b/51/f3/9b51f315-2ffa-f9d0-0ae9-d0c66e7daf0e/AppIcon-0-0-1x_U007epad-0-1-85-220.png/434x0w.png)

**Developer:** [Byeongsu KIM](https://apptail.io/developer/byeongsu-kim-iYKrib)
**Category:** Utilities
**Rating:** 4.5/5 (2 ratings)
**Price:** Free
**Bundle ID:** com.rootbly.rootblysub
**Store:** Apple App Store
**Country:** Japan
**Version:** 3.3.0 (released 2026-10-29)
**Original Release:** 2026-04-09
**Languages:** English

**App Store Link:** [Download on Apple App Store](https://apps.apple.com/jp/app/app/id6761355562)
**AppTail Page:** [https://apptail.io/app/rootbly-ai-subtitle-qchA/japan](https://apptail.io/app/rootbly-ai-subtitle-qchA/japan)

## Rootbly Description
Watch foreign YouTube videos with translated subtitles.

RootblySub auto-translates YouTube subtitles into your language. Just paste a URL, and AI generates subtitles you can watch instantly in our built-in player.

◆ CORE FEATURES

• AI Subtitle Translation — 15 languages including English, Korean, Japanese, Chinese, Spanish, French, and more
• Built-in Video Player — Translated subtitles displayed in real-time over the video
• Subtitle Sync Control — Manual offset adjustment within ±5 seconds
• Subtitle Size Settings — Small/Medium/Large presets with fine-grained control
• Original Text Toggle — View translation alongside or without the original

◆ YOUTUBE BROWSING

• YouTube Search — Find videos directly within the app
• Channel Browser — Explore videos, Shorts, playlists, and live streams
• Channel Favorites — Save channels you watch frequently
• Clipboard Detection — Auto-detect copied YouTube URLs

◆ TRANSLATION JOB MANAGEMENT

• Real-time Progress — Track each stage: downloading → transcribing → translating
• Push Notifications — Get notified the moment translation is complete
• Job History — Manage all your translation requests in one place

◆ CONVENIENCE

• Sign in with Google / Apple or use Guest mode
• YouTube Premium integration for ad-free viewing
• Korean & English UI
• Fullscreen landscape mode

Enjoy YouTube content from around the world — no language barriers.

Terms of Use: 
Privacy Policy: 

---

## Rootbly Screenshots
- [Screenshot 1](https://is1-ssl.mzstatic.com/image/thumb/PurpleSource211/v4/5c/9e/a3/5c9ea331-33d2-7bdc-1a7b-6262d85ea669/01-hero.png/1284x2778.png)
- [Screenshot 2](https://is1-ssl.mzstatic.com/image/thumb/PurpleSource221/v4/b0/e2/e8/b0e2e89e-b785-9f82-3597-28607da137af/02-device-top.png/1284x2778.png)
- [Screenshot 3](https://is1-ssl.mzstatic.com/image/thumb/PurpleSource211/v4/d0/f4/dc/d0f4dc9d-9247-13fb-a9e6-3be0e6c562fd/03-device-bottom.png/1284x2778.png)
- [Screenshot 4](https://is1-ssl.mzstatic.com/image/thumb/PurpleSource221/v4/82/a4/0f/82a40f5b-a2cb-6a88-d8cf-cbc89d558421/04-device-top.png/1284x2778.png)
- [Screenshot 5](https://is1-ssl.mzstatic.com/image/thumb/PurpleSource211/v4/01/39/a9/0139a9d7-7ffa-e023-34ac-7524ba32fa5d/05-device-bottom.png/1284x2778.png)
- [Screenshot 6](https://is1-ssl.mzstatic.com/image/thumb/PurpleSource211/v4/93/10/54/93105476-c073-0eb7-3e74-205f678f232d/06-device-top.png/1284x2778.png)
- [Screenshot 7](https://is1-ssl.mzstatic.com/image/thumb/PurpleSource211/v4/b0/a8/3f/b0a83fa0-391f-94d0-ae6d-c33f9b3cd108/07-no-device.png/1284x2778.png)

## Rootbly Rating Breakdown in Japan
- 5 stars: 1 (50%)
- 4 stars: 1 (50%)
- 3 stars: 0 (0%)
- 2 stars: 0 (0%)
- 1 stars: 0 (0%)






## Rootbly Available In
- [Japan](https://apptail.io/app/rootbly-ai-subtitle-qchA/japan)
- [United States](https://apptail.io/app/rootbly-ai-subtitle-qchA/united-states)
- [Vietnam](https://apptail.io/app/rootbly-ai-subtitle-qchA/vietnam)
- [United Kingdom](https://apptail.io/app/rootbly-ai-subtitle-qchA/united-kingdom)
- [Egypt](https://apptail.io/app/rootbly-ai-subtitle-qchA/egypt)
- [Saudi Arabia](https://apptail.io/app/rootbly-ai-subtitle-qchA/saudi-arabia)
- [South Korea](https://apptail.io/app/rootbly-ai-subtitle-qchA/south-korea)
- [Germany](https://apptail.io/app/rootbly-ai-subtitle-qchA/germany)
- [Dominican Republic](https://apptail.io/app/rootbly-ai-subtitle-qchA/dominican-republic)
- [Algeria](https://apptail.io/app/rootbly-ai-subtitle-qchA/algeria)
- [France](https://apptail.io/app/rootbly-ai-subtitle-qchA/france)
- [Ghana](https://apptail.io/app/rootbly-ai-subtitle-qchA/ghana)
- [Hungary](https://apptail.io/app/rootbly-ai-subtitle-qchA/hungary)
- [Indonesia](https://apptail.io/app/rootbly-ai-subtitle-qchA/indonesia)
- [Israel](https://apptail.io/app/rootbly-ai-subtitle-qchA/israel)
- [India](https://apptail.io/app/rootbly-ai-subtitle-qchA/india)
- [Italy](https://apptail.io/app/rootbly-ai-subtitle-qchA/italy)
- [Jordan](https://apptail.io/app/rootbly-ai-subtitle-qchA/jordan)
- [Kenya](https://apptail.io/app/rootbly-ai-subtitle-qchA/kenya)
- [Cambodia](https://apptail.io/app/rootbly-ai-subtitle-qchA/cambodia)
- [Lebanon](https://apptail.io/app/rootbly-ai-subtitle-qchA/lebanon)
- [North Macedonia](https://apptail.io/app/rootbly-ai-subtitle-qchA/north-macedonia)
- [Mauritius](https://apptail.io/app/rootbly-ai-subtitle-qchA/mauritius)
- [Nicaragua](https://apptail.io/app/rootbly-ai-subtitle-qchA/nicaragua)
- [New Zealand](https://apptail.io/app/rootbly-ai-subtitle-qchA/new-zealand)
- [Oman](https://apptail.io/app/rootbly-ai-subtitle-qchA/oman)
- [Philippines](https://apptail.io/app/rootbly-ai-subtitle-qchA/philippines)
- [Poland](https://apptail.io/app/rootbly-ai-subtitle-qchA/poland)
- [Paraguay](https://apptail.io/app/rootbly-ai-subtitle-qchA/paraguay)
- [Senegal](https://apptail.io/app/rootbly-ai-subtitle-qchA/senegal)
- [Türkiye](https://apptail.io/app/rootbly-ai-subtitle-qchA/turkey)
- [Taiwan](https://apptail.io/app/rootbly-ai-subtitle-qchA/taiwan)
- [Ukraine](https://apptail.io/app/rootbly-ai-subtitle-qchA/ukraine)
- [Uzbekistan](https://apptail.io/app/rootbly-ai-subtitle-qchA/uzbekistan)
- [Yemen](https://apptail.io/app/rootbly-ai-subtitle-qchA/yemen)
- [Angola](https://apptail.io/app/rootbly-ai-subtitle-qchA/angola)
- [South Africa](https://apptail.io/app/rootbly-ai-subtitle-qchA/south-africa)
- [Australia](https://apptail.io/app/rootbly-ai-subtitle-qchA/australia)
- [Brazil](https://apptail.io/app/rootbly-ai-subtitle-qchA/brazil)
- [Switzerland](https://apptail.io/app/rootbly-ai-subtitle-qchA/switzerland)
- [Chile](https://apptail.io/app/rootbly-ai-subtitle-qchA/chile)
- [China](https://apptail.io/app/rootbly-ai-subtitle-qchA/china)
- [Czechia](https://apptail.io/app/rootbly-ai-subtitle-qchA/czechia)

---

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