PO Validator B2B vs PS: Checkout Rules
Two Shopify apps, side by side: detected stores, momentum, reviews, plans, listed features and who runs each. Store counts as of Oct 13, 2026 for PO Validator B2B, Oct 14, 2026 for PS.
The short answer
- Both list a free plan. Paid plans start at $4.99/month for PO Validator B2B and $29.99/month for PS.
Head to head
Free
- · Built-in errors in EN, DE, FR, and ES
- · Required PO field enforced at checkout
Starter
- · Everything in Free
- · Minimum and maximum length validation
- · Regex patterns for ERP and SAP formats
- · Required prefix rule (e.g. "PO-")
Pro
- · 24/7 email support
- · Character rules: whitelist, no spaces
- · Custom error messages per language
- · Custom feature requests welcome
- · Everything in Starter
- · Personal onboarding session
Free
- · PO Box blocking in 10+ languages
- · Social CTA: WhatsApp, IG, FB, X, TikTok
- · Thank-you verification banner
- · Unlimited orders, 1 active rule
- · Your own custom error message
Pro
- · Blocked-orders log with CSV export
- · Checkout banners with conditions
- · Everything in Free
- · One-click product upsell at checkout
- · Post-purchase survey saved to the order
- · Savings dashboard + analytics
Pro Annual
- · All 5 validation rules, not just PO Box
- · Everything in Pro, billed yearly
- · Lock in your price for 12 months
- · One-click product upsell at checkout
- · Post-purchase survey saved to the order
- · Save 33% vs paying monthly
Coverage counts what each App Store listing names. Every feature, checked off app by app, is in Shoplist.
See every featureB2B merchants must attach a Purchase Order number to every order, but Shopify provides no native way to enforce this. Buyers skip the PO field or enter invalid data, causing fulfillment delays and ERP mismatches. PO Validator solves this with server-side validation via Shopify Functions. Buyers cannot complete checkout without a valid PO number.
Most stores pay one app to stop bad addresses, another to upsell at checkout, and a third to survey buyers. That is three bills and three scripts in one checkout. This app does all three. Block PO Box, Postfach and Packstation addresses in 10+ languages, require a house number, and restrict zip codes, countries, or order values. Add one-click upsell offers from a collection or your best sellers.
- Server-side checkout validation that buyers cannot skip or bypass
- Flexible rules: length limits, required prefix, and regex for ERP formats
- Character rules: whitelist allowed characters and block unwanted spaces
- Regex rules: validate PO formats against ERP and SAP number patterns
- Block PO Box, zip code, country, and order value violations at checkout
- Hide, rename, and reorder shipping and payment methods
- Add checkout banners and Thank You page blocks with live preview
- Track blocked orders and checkout violations in real-time analytics
All the numbers
Every figure, side by side
A green dot marks the app ahead on a measured figure. Estimates, gaps and apps that leave no storefront trace never take the lead.
Adoption
| Measure |  PO Validator B2B |  PS |
|---|---|---|
| Detected stores | Not published | Not published |
| Net store change, 28 days | 0 | 0 |
| Stores added, 28 days | Not enough data | Not enough data |
| Big-brand share | Not enough data | Not enough data |
| Top store categories | Not published | Not published |
| Top store countries | Not published | Not published |
Reviews
| Measure | PO Validator B2B | PS |
|---|---|---|
| App Store rating | Not published | 5.0 ★ |
| App Store reviews | Not published | 1 |
| New reviews, 28 days | Not enough data | Not enough data |
| Reviewers a year or more in | Not enough data | Not enough data |
Pricing
| Measure | PO Validator B2B | PS |
|---|---|---|
| Free plan | Yes | Yes |
| Lowest paid monthly plan | $4.99/month(ahead) | $29.99/month |
| Longest free trial | 7 days | 1 days |
| Plans listed | 3 | 3 |
Listing
| Measure | PO Validator B2B | PS |
|---|---|---|
| Shopify category rank | #272 | #103(ahead) |
| Shopify App Charts | Not on this week’s charts | Not on this week’s charts |
| Built for Shopify | No | No |
| Launched | Jun 8, 2026 | Jun 26, 2026 |
| Languages | 3 | 1 |
| Developer | byKlemm | Partners Studio |
FAQ
PO Validator B2B and PS: common questions
- Is PO Validator B2B or PS cheaper?
- Both list a free plan. Paid plans start at $4.99/month for PO Validator B2B and $29.99/month for PS. Shoplist compares base prices only between monthly plans in the same currency; usage charges and annual plans vary, so check each plan’s limits.
- Where does this comparison’s data come from?
- Shoplist crawls Shopify storefronts to detect which apps each store runs, and reads each app’s Shopify App Store listing for reviews, pricing, features and integrations. Store counts are as of Oct 13, 2026 for PO Validator B2B, Oct 14, 2026 for PS; estimated figures are labeled.
How Shoplist compares apps
Store counts come from Shoplist’s crawl of Shopify storefronts, which detects the apps each store runs; they are as of Oct 13, 2026 for PO Validator B2B, Oct 14, 2026 for PS. Reviews, ratings, plans, features and integrations come from each app’s Shopify App Store listing. 28-day figures are labeled when estimated, and a figure that is missing or estimated never decides who leads. Read the methodology.