Free tool

PO box and street number address checker

Direct answer. Paste one address line per row and this page marks the ones that look like a PO box, the ones with no street number, and the ones worth a manual look. It runs in your browser and sends nothing anywhere. Use it to build a test list before you write a billing rule at checkout.

The tool uses a short, generic pattern list. It does not show what any app matches: to see how a real checkout rule behaves, run your list through the PO Box Blocker — AddressFence simulator (Shopify App Store) before publishing a rule.

Install PO Box Blocker — AddressFence

Check your address lines

Address line 1, one per row

Install AddressFence — Free blocks shipping PO Boxes and parcel lockers; a billing rule is on a paid plan

What the checker flags

Looks like a PO box: PO Box, P.O. Box, Post Office Box, POB or a bare “Box 12” followed by a number.
No street number: the line has no digit at all, for example “Main Street” or a house name.
Review: a rural route or similar line that contains a box number and may be a real delivery address.
Looks OK: everything else, including real streets such as Boxwood Road.

A house name with no number can be a real address in some countries. Decide your own rule for those, and see house names and required street numbers.

From a test list to a checkout rule

Shopify’s built-in, no-code checkout settings cover the shipping address only (why they do not reach billing). A billing-address rule needs an app or a checkout validation function. Write the expected result for each line first, then test every line in the simulator, as in the PO box spelling test list.

Install the PO box blocker on the Shopify App Store

What this page is not

Not a list of every pattern AddressFence matches; the simulator result is what counts.
Not legal advice or a statement about carrier or card-network rules.
Not a data collector: addresses you paste stay in this browser tab.