Bad addresses cost you twice: the carrier fee and the reship. Address Verifier catches them before they ship. It checks every address against carrier and postal data, down to the apartment. Customers fix their own address in one click; on Shopify Plus, right in checkout. It covers express orders that bypass address checks. You set the rules: block PO boxes, missing house numbers, and bad ZIP codes. It never blocks a real sale: we suggest the fix, the customer decides. Setup takes no code.