PO Number Validator
Require purchase order numbers at B2B checkout and enforce your exact PO format. No missed orders, no invalid numbers, no chasing customers after the sale.
A purchase order field isn’t a purchase order rule.
Shopify’s native B2B checkout includes a purchase order field — but it can’t make the field required, and it can’t check that buyers enter a valid format. Orders arrive with the field left blank, or filled with a number that doesn’t match anything your accounts payable team can use.
Every one of those orders becomes a follow-up email, a delayed fulfilment, and a manual correction. PO Number Validator turns the PO field into an enforced rule, so the order is correct before it’s ever placed.
Set your rules once.
1. Install on your Plus store
Install the app and choose a plan. Both plans include a 7-day free trial, so you can configure and test everything before any charge applies.
2. Define your PO rules
Open the app dashboard inside Shopify Admin. Decide whether a PO number is required, set a format with pattern, prefix, and length rules, and write the message buyers see if they get it wrong. Apply a built-in preset to start fast.
3. Activate the checkout validation
In Settings → Checkout → Checkout rules, switch on PO Number Validator. Validation runs server-side, so your rules apply to every checkout type a buyer can use.
4. Orders arrive clean
When a B2B buyer places an order, their purchase order number is checked against your rules. If it’s missing or invalid, checkout is blocked with a clear message telling them exactly what to fix.
Built for real B2B operations.
Required PO numbers
Make a purchase order number mandatory on B2B checkout. Buyers cannot place an order until the field is filled — no gap, no exceptions, no after-the-fact follow-up.
Format enforcement
Enforce your exact PO format with pattern rules, required prefixes, and minimum or maximum length. A number that doesn’t match your back office is rejected at checkout, not discovered later.
Works on every checkout type
Validation runs server-side as a Shopify Function, so your rules apply to standard checkout, express checkouts, and accelerated wallets alike. There’s no path a buyer can slip an invalid order through.
Translated error messages
Selling across markets? On the Business plan, translate the checkout error messages per market, so a German buyer sees German and a French buyer sees French — automatically, based on the buyer’s locale.
Targeting and thresholds
Apply validation to all customers, B2B customers only, or specific customer tags. Optionally require a PO only above a minimum order value, so small orders aren’t held up.
ERP format presets
On the Business plan, apply a built-in preset for a common PO format — SAP, US Government (GSA), or a standard prefix-and-dash pattern — then fine-tune to match what your back office expects.
GDPR-friendly by design
We don’t store any customer data. The app only knows about your shop domain, your OAuth token, and the validation rules you configured. See the Privacy Policy for full detail.
What you need.
- An active Shopify Plus plan.
- B2B enabled, with at least one company and company location.
- Access to checkout rules to activate the validation.
Two plans. Both with a free trial.
Pro — $29 per month. PO number validation at checkout, custom format rules, custom error messages, and email support with a one business day response.
Business — $79 per month. Everything in Pro, plus translated error messages for every market you sell in, ERP format presets, and priority chat support with a four-hour response.
Both plans include a 7-day free trial and are billed through your Shopify invoice along with your other apps. No per-order fees, no hidden costs.
Common questions.
Doesn’t Shopify B2B already have a PO field?
It has the field, but not the rule. Native B2B checkout can’t make the purchase order field required and can’t validate the format a buyer enters. PO Number Validator adds exactly that enforcement.
Does it work with express and accelerated checkouts?
Yes. Validation runs server-side as a Shopify Function, so it applies on every checkout type — not just the standard checkout page.
When does the buyer see the error?
Validation runs when the buyer places the order. If the PO number is missing or doesn’t match your format, checkout is blocked and a clear message explains what to correct, including your format example.
Can I show error messages in other languages?
Yes, on the Business plan. You can translate every checkout error message per market, and the buyer is shown the message in their own language automatically.
What happens when I uninstall?
Your validation rule stops applying immediately. All app sessions in our database are deleted within 48 hours of uninstall, per our privacy policy.
7 days free, no card upfront.
Install on your Plus store, set your PO rules once, and see clean B2B orders from your first day. If it doesn’t work for you, uninstall before the trial ends and you’re not charged.