modlet: Block PO Box & Lockers

Protect your shipping margins with reliable, global PO Box blocking. Built natively into Shopify Checkout, it physically blocks checkout completion for restricted addresses—ensuring 100% reliability. Why offer a generous free tier? Built by a veteran cloud architect, our highly efficient infrastructure keeps costs low, and we love helping new stores get off the ground. Grow with us for free, and upgrade to Pro as your volume increases or when you need granular, custom shipping rules.