CaptiPrep

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.