Shopify Functions
Shopify Cart and Checkout Validation
Enforce order rules at Shopify checkout with validation Functions: minimum order quantities, purchase limits, restricted products and compliance checks.
Some orders should never go through. Below your minimum, over a purchase limit, mixing products that cannot ship together, or missing something your industry requires. Checkout validation enforces those rules at the last possible moment, before money changes hands.
Rules the storefront cannot enforce alone
Theme and cart tweaks can be bypassed. A validation Function runs at checkout on Shopify’s infrastructure, so the rule holds no matter how the customer got there.
Block clearly, not silently
A blocked checkout with no explanation just loses the sale. We pair validation with clear messaging so the customer knows exactly what to change, which turns a hard stop into a fixable step.
Built for the messy cases
Regulated goods, region restrictions, wholesale minimums, bundle requirements. These are the rules that are painful to enforce well, and exactly the ones we build for.
What we build
Order minimums and limits
Enforce minimum order values, maximum quantities and per-customer purchase limits.
Restricted products
Stop incompatible or regulated items being bought together, or shipped where they cannot go.
Compliance checks
Gate checkout on the conditions your industry or region requires before an order can proceed.
Clear customer messaging
Explain exactly why a cart is blocked and what the customer needs to change.
Questions, answered
What can checkout validation actually block?
Carts that miss a minimum, exceed a limit, mix restricted products, or fail a rule you define. The customer sees a clear message and cannot check out until it is resolved.
Do validation errors show in express checkouts?
Yes. Validation errors appear in the cart, in checkout, and in express checkouts like Shop Pay, PayPal, Google Pay and Apple Pay, so the rule holds however the customer pays.
Can it show a warning instead of blocking?
Validation is designed to block a checkout that breaks a hard rule. For softer nudges we combine it with checkout UI extensions that warn without stopping the order.
Does validation need Shopify Plus?
Custom validation Functions like the ones we build need Shopify Plus, because Shopify only allows custom apps with Functions on Plus. On other plans you can use public App Store apps that include validation, or cart-level logic, which is easier to bypass.
Ready to build a store worth talking about?
Tell us where your store is today and where you want it to go. We reply within two working days with a clear next step.