About
Built by flippers, for flippers.
CritFlip exists because eBay sourcing was eating eight hours of our day and we wanted those hours back. We built it for ourselves first. The fact that it works for everyone else is a happy accident.
Why we built it.
eBay's search wasn't built for people who buy 100 items a month. It was built for someone looking for a single vintage lamp. If you're sourcing for resale, the friction — bad filters, slow refresh, no blocklists, no margin math — compounds until you're spending more time scrolling than shipping.
CritFlip is the layer we wanted: a HUD that lets us see what matters, alerts that fire the second something good drops, and a score that tells us in one glance whether it's worth the buy.
The company behind it.
CritFlip is built and operated by West Michigan 3PL Inc, a Michigan corporation based in Allegan. We run a working reselling and logistics operation — CritFlip is the software we use every day to keep it profitable. We dogfood every release.
Who CritFlip is for
If you're any of these, you're our people.
Solo flippers
You source, list, ship, and pack — alone. CritFlip cuts your sourcing time in half so the rest of the day belongs to you.
Side-hustle resellers
You have a day job. CritFlip pings you only on listings worth interrupting it for — and lets the rest pass.
Multi-channel sellers
You source on eBay and resell on eBay, Poshmark, StockX, your own Shopify, and Mercari. CritFlip handles the eBay sourcing layer cleanly.
Reselling teams
Connect every team member's eBay account under one CritFlip subscription. Shared blocklists, shared filter macros, separate buyer histories.