Identify a coin, value a collection — without leaving the photo.
A private numismatics tool. Two photos return an attribution, an NGC grade hypothesis, and a market value sourced from manual sale comps. Built solo on Next 15, Drizzle, and Claude.
What's interesting about the build
Tracking a coin collection is hard once you're past a handful: what you own, what it's worth, where it lives, what new finds are. Most collectors live in spreadsheets and memory. This tool puts it in one place — scan any coin or set, get an attribution and a market value, the result lands in a searchable, exportable inventory. Built on Next 15, Drizzle / Neon, R2, and Anthropic Claude.
The collection page treats the URL as source of truth. Every filter, sort, and page index serializes into search params and is parsed once on the server — no client store, no cache. Bookmarks work, the back button works, and the export routes reuse the same parser so the displayed row set and the exported row set can never drift.
Coin identification accuracy is measured, not assumed. A vitest harness runs labeled fixtures through the Claude vision adapter and reports per-field accuracy and confidence calibration. The harness surfaced a real limit: Claude vision handles Morgans and Lincolns well but stalls on Presidential dollars, so the series is scope-deferred rather than shipped with shaky accuracy.
Roadmap: a tree-style inventory visualizing the full universe of US coin types alongside which ones your collection holds (instant gap-finder), and adding paper money as a first-class scan target alongside coins and sets.