YTT - YouTube Transcript Translator

A simple tool for learning languages through YouTube videos.

What it does

• Fetches transcripts from YouTube videos via yt-dlp
• Translates them using LibreTranslate (self-hosted, no API keys)
• Shows original and translation side-by-side with synchronized scrolling
• Saves transcripts in per-video folders (transcripts/{video_id}/)
• Mobile fullscreen mode with 50/50 split-screen and paragraph snapping
• Desktop fullscreen with paragraph linking and hover highlighting
• Translation history with search and review

Tech Stack

Layer	Technology
Frontend	SvelteKit 5 (runes), Carbon Design System v0.99.1
Backend	FastAPI, yt-dlp
Translation	LibreTranslate
Storage	JSON files (no database)
Deployment	Single Docker container, multi-stage build

Quick Start

git clone https://github.com/keesfluitman/ytt.git
cd ytt
docker build -t ytt:latest .
docker compose up -d

Open http://localhost:8000. First startup is slow while LibreTranslate downloads language models.

Requirements: Docker, ~4GB RAM, ~10GB disk.

Using your own LibreTranslate

Set LIBRETRANSLATE_URL in your .env or docker-compose.yml and run just the YTT container.

Development

# Backend
cd backend && python -m venv venv && source venv/bin/activate
pip install -r requirements.txt && uvicorn main:app --reload

# Frontend
cd frontend && pnpm install && pnpm dev

# LibreTranslate
docker run -d -p 5000:5000 libretranslate/libretranslate

Frontend dev server: http://localhost:5173

API

Endpoint	Method	Description
/api/youtube/fetch	POST	Fetch and translate YouTube transcript
/api/translate	POST	Translate text (supports entry_id for updating existing entries)
/api/history	GET	List translation history
/api/history/{id}	GET/PUT/DELETE	Manage individual entries
/api/version	GET	Build info (version, date, commit)
/health	GET	Health check

Project Structure

ytt/
├── frontend/          # SvelteKit 5 SPA
│   └── src/routes/    # Pages: translate, history, view/[id], settings
├── backend/           # FastAPI
│   └── app/
│       ├── api/       # Endpoints (translate, youtube, history)
│       └── services/  # Business logic (translator, youtube, history)
├── Dockerfile         # Multi-stage build (Node.js -> Python)
└── docker-compose.yml

License

MIT

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Built for learning languages, one YouTube video at a time.