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Subtide

AI-powered video subtitle translation for YouTube, Twitch, and any video site.


  • Real-time Translation - Translate video subtitles on the fly
  • AI Transcription - Generate subtitles with Whisper when none exist
  • Streaming Mode - See subtitles within seconds, not minutes (Tier 4)
  • 13+ Languages - Support for major world languages
  • Context-Aware - Merges partial sentences for better translation quality
  • Smart Caching - Translations cached for instant replay
  • YouTube - Full support including embedded players
  • YouTube Shorts - Pre-translation mode for instant subtitles while swiping
  • Twitch - Live stream translation support
  • Generic Sites - Works on any site with <video> elements
  • Modern UI - Clean dark theme with teal accents
  • Draggable Subtitles - Position subtitles anywhere on screen
  • Adjustable Size - Small, Medium, Large, and XL subtitle options
  • Dual Subtitles - Show original + translated text simultaneously
  • Keyboard Shortcuts - Toggle subtitles (T), switch mode (D), download (S)
  • Subtitle Export - Download as SRT, VTT, or TXT
  • Flexible API - Works with OpenAI, OpenRouter, or any OpenAI-compatible API
  • Local LLM Support - Use LM Studio, Ollama, or other local models
  • Apple Silicon Optimized - MLX Whisper backend for M1/M2/M3/M4 Macs
  • GPU Acceleration - CUDA support for NVIDIA GPUs


This project is fully open-source with no paid tiers. The “Tiers” refer to different technical configurations:

FeatureTier 1Tier 2Tier 3Tier 4
YouTube Captions
Whisper Transcription
API Key LocationBrowserBrowserServerServer
Force AI Generation
Progressive Streaming
  • Tier 1 (Standard) - Uses existing YouTube captions + your API key
  • Tier 2 (Enhanced) - Whisper transcription + your API key
  • Tier 3 (Managed) - Server handles API keys (for shared deployments)
  • Tier 4 (Stream) - Progressive translation with instant subtitle display

LanguageCodeLanguageCode
EnglishenJapaneseja
SpanishesKoreanko
FrenchfrChinese (Simplified)zh-CN
GermandeChinese (Traditional)zh-TW
PortugueseptArabicar
RussianruHindihi
Italianit

Subtide is released under the MIT License.