FanFan Cards — AI Context Lookup & Vocab

FanFan Cards turns the English you actually read every day into vocabulary you own. Select a word, understand it here. The AI explains a word in the sentence it appears in — not the most common dictionary sense, but what it means right here. The "lock" in "lock a table for minutes" is not a padlock. Words you looked up light up next time. Turn on FanFan mode and words from your notebook are marked wherever they appear. Click one to revisit the stored meaning, sentence and examples — no additional AI call, no additional cost. Save to your notebook, review with the sentence. Every saved word keeps the sentence and the page it came from — word lists stripped of context do not stick. Reviews are scheduled by spaced repetition. Translation too. Hover and hold one key for a paragraph, one shortcut for the page; bilingual subtitles on YouTube, Bilibili and any video with a subtitle track, and on players that draw their own subtitles once you point at the subtitle area. Translations are appended below the original. Translation is free; context needs your own AI key. Without a key, lookups and translation go through Google Translate: dictionary senses, page and subtitle translation, just no "what it means here". For that, add a key from DeepSeek, Anthropic (Claude), OpenAI, Gemini, or any OpenAI-compatible endpoint. Your data stays yours. Cards live only in your own browser; settings and API keys can be saved to a folder you choose, synced with your browser account when enabled, or kept local-only. There is no server behind this extension; the developer receives nothing. For backup and multi-device use, sync to your own private GitHub repository, stored as Markdown a human can read. Open source: https://github.com/CarGod/fanfan-cards