ShipPeek — Margin Copilot

See your true net margin live while you list, and get warned before you publish a money-loser.

Stop publishing money-losers. ShipPeek sits inside your eBay and Poshmark listing flow and shows your TRUE net margin live (after fees, shipping, and the costs most sellers forget) then turns red and warns you before you hit Publish on a listing that would actually lose money. Unlike a standalone fee calculator, you don't type anything into a separate tool. ShipPeek reads the listing you're already creating and does the math automatically, right on the page. What it accounts for: category-aware eBay final-value fees, payment + per-order fees, promoted-listing %, shipping with dimensional weight (USPS), free-shipping loss, and a returns buffer you control. Private by design: all calculations happen locally in your browser. Your listing data never leaves your device. No analytics, no tracking, no remote code. Free: live net margin on eBay. Pro (subscription): the pre-publish loss warning and Poshmark support. Payments handled by ExtensionPay/Stripe. ShipPeek is independent and not affiliated with eBay, Poshmark, or any carrier.