PO box rule test list
PO box spellings and look-alike street names: test your Shopify billing rule before you publish
Direct answer. A PO box rule fails in two ways: it misses a spelling such as Post Office Box or a bare “Box 12”, or it stops a real street such as Boxwood Road. Write a short list of both kinds, run each address through the AddressFence simulator before you publish, and use one-click rollback if a published rule stops a real customer.
PO Box Blocker — AddressFence (Shopify App Store). Free blocks PO Boxes and parcel lockers on the shipping address at checkout, plus a small set of ZIP rules. Street-number checks and billing-address rules are on a paid plan. It lets you test any address in the simulator before publishing. This page is a test list, not a description of every pattern the app recognises: the simulator result is what counts.
Related: B2B PO Guard — Require PO — B2B purchase order number required at company checkout.
Free check first: PO box and street number address checker runs in your browser and sends nothing. Paste addresses and see which look like a PO box or lack a street number.
Install PO Box Blocker — AddressFence
Why test spellings and look-alikes
Customers write a PO box many ways, and real streets can share the same letters. Native Checkout Blocks can already block a PO box on shipping for all merchants (17 June 2026 changelog; Help). Shopify’s built-in, no-code checkout settings cover the shipping address only, so the billing line is where your own rule has to hold up. See why built-in rules do not reach billing.
A test list to paste into the simulator
| Address line 1 | What you probably want |
|---|---|
| PO Box 123 | Block |
| P.O. Box 123 | Block |
| P O Box 123 | Block |
| Post Office Box 123 | Block |
| POB 123 | Block |
| Box 12 | Block |
| 123 Boxwood Road | Allow (real street) |
| 45 Boxer Lane | Allow (real street) |
| 1 Post Office Square | Allow (real street) |
| Rural Route 2 Box 14 | Your call: a real rural address that contains “Box” |
| Main Street | Block if you require a street number |
Add the odd cases from your own order history: abbreviations, a PO box typed in the second address line, extra spaces, lower case.
Install the PO box blocker, then run the test list
Run it
- Write the expected result for each line before you test.
- Run every line through the simulator for a billing address and mark any mismatch.
- Adjust the rule, test again, and only then publish.
- After publishing, place one test order for a blocked and an allowed address.
- If a rule stops a real customer, roll it back with one click, fix it, and re-test.
Keep it short
Ten to twenty lines catch most surprises. Keep the list in your store notes and re-run it after any rule change.
What this page is not
- Not a list of every pattern AddressFence matches; use the simulator for that.
- Not legal advice or a statement about carrier or card-network rules.
Related pages
- Test a Shopify address rule in a simulator before you publish
- PO box blocker for the billing address
- Require a street number at Shopify checkout
- PO box blocker apps: which ones check billing
- PO Box Blocker — AddressFence
Not legal advice. Re-check the cited law and the current app page before you rely on this page.