Vayu Address Validator

Checks the shipping address at checkout and stops it with a clear message when it breaks your rules.

Install it from the Shopify App Store, or open it from Apps in your Shopify admin.

Blocks PO Boxes at checkout, including P.O. Box, Post Office Box, Postfach, Boîte postale and PMB
Optional blocks for APO/FPO/DPO military addresses and parcel lockers
Require an apartment or unit number for the postal codes you choose
Require a phone number for delivery
Block or allow countries, states / provinces and postal code patterns
Maximum address line length for carrier labels, and Latin-only addresses
Limit any rule to certain products or collections, e.g. hazardous items