A marketplace for pedigree livestock, built like it matters.
This is a working, interactive demo — not a mockup. Faceted search runs the way Postgres would serve it, the auction below shows a race-safe bidding flow (the locking logic is in the code panel), and the dashboards are hand-built SVG. Every piece maps to a deliberate engineering decision, shown in the Under the hood panel.
Browse the market
Filter live, with fuzzy breed matching and faceted narrowing. The same predicates map straight onto an indexed Postgres query — see the SQL →
Live auction — and why a race can’t mint two winners
Place a bid. Then tick “simulate a competing bid at the same instant” and watch the transaction log: the row lock serialises both bids, re-validates the loser against the new floor, and rolls it back. One winner, always.
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The data-heavy views sellers actually need
Built with D3.js — interactive, animated, and live-wired to the filters above. Try filtering the marketplace, then watch these redraw. Same custom-dataviz muscle behind the D3 interface I wrote for the fully custom restaurantwang.at CMS.
Price range by species
Bid activity
Average price by species
Listings by status
The engineering behind the demo
This is the part most proposals can’t show. Every claim above is backed by real, idiomatic code — the schema, the race-safe bid service, the search query, and the RBAC guard.