Block PO boxes and custom address patterns. Protect your checkout with address and customer‑group rules. Detect and block PO boxes and any unwanted address patterns (like post‑office references, zip codes or cities). Create custom filters to avoid high‑risk locations, reducing failed deliveries. Customize error messages and integrate seamlessly into Shopify Checkout without editing code. Protect your checkout with address and customer‑group rules. Detect and block PO boxes and any unwanted address patterns (like post‑office references, zip codes or cities). Create custom filters to avoid high‑risk locations, reducing failed deliveries. Customize error messages and integrate seamlessly into Shopify Checkout without editing code. more Works with all Shopify plans; toggle rules with a click; no code needed Customize the messages shoppers see when rules trigger Block PO boxes & unwanted address patterns at checkout Create custom rules by keywords, cities or ZIP codes