Whatnot is where a lot of trading cards, comics, Funko Pops, and sneakers get sold now, live, one auction at a time. If you sell there, or you're studying the market, you want numbers: which sellers move the most items, who is live right now, how many people are watching, and what a card goes for when it's listed.

The first thing most people search is "Whatnot API". There is one, but it probably isn't the one you want. So this post covers both: what the official Whatnot API gives you, and how to build a small Whatnot scraper in Node.js for the public data it doesn't cover.

The scraper is one file, no npm dependencies, Node 18+.…