CaptiPrep

About

CaptiPrep is an AI-assisted tool for English learners that helps you preview key vocabulary and expressions from subtitles before watching a YouTube video. Learn first, watch later — more efficient and less boring.

Main features

- Subtitle preview: automatically extracts key words and phrases from English subtitles.
- Smart filtering: AI pre-filters combined with manual selection to produce a study list that fits you.
- One-click card creation: generate study cards with definitions, phonetics, example sentences and notes.
- In-page overlay: operate directly on the YouTube page without switching away.
- Vocabulary notebook: saves study history and favorites; supports selecting, deleting and exporting for review.   
- Privacy-first local storage: API keys and related settings are stored only in the local options page.
    

How to use

1. Install the extension and open a YouTube video that has English subtitles.
2. Click the extension icon to open the panel.
3. Extract subtitles → choose words/phrases → generate cards → study.
4. Use the entry on the right to open the “Vocabulary Notebook” for review and export.
    
Settings

- Configure LLM provider, model and API key on the Options page (stored locally).
- Supported providers: OpenAI, Anthropic Claude, Google Gemini, and OpenAI-compatible providers.
- For best results, use videos with English subtitles.

With CaptiPrep, turn “watching videos to learn English” into a planned, reviewable, context-based, and efficient learning workflow.