I kept losing my reading flow every time I hit an unfamiliar word. The usual fix: open a new tab, search, scroll past ads, come back. Costs about 30 seconds of focus each time. Multiply that by 10 lookups in one article and it adds up fast.

Google Dictionary extension solved the tab-switching problem but never went further than static definitions. I wanted something smarter.

So I built QuickDef, a Chrome extension that sends the surrounding sentence to GPT-4o-mini alongside the word, so the definition matches what the word actually means in that context, not just the dictionary default.

Stack: - Chrome Extension (Manifest V3) - Node.js + TypeScript + Express (backend on Railway) - OpenAI GPT-4o-mini - Supabase (auth + database) - Next.js landing page on Vercel

Freemium: 10 free AI lookups/day, unlimited dictionary mode always free.

Would love feedback from the HN community, especially on the freemium limit and anything technically questionable.

Chrome Web Store: https://chromewebstore.google.com/detail/ioepkncpchchdiookgp... Website: https://www.quickdef.app