Checkout Validation
Rules that cannot be bypassed
Validate orders at Shopify checkout using Shopify Functions. Quantity limits, customer caps, and cart restrictions are enforced server-side, so customers can't switch them off in the browser.
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Why It Matters
Cart-only validation is not enough
Cart shows warnings. Checkout enforces rules.
Both layers work together. Cart validation tells customers about a limit early, and checkout validation blocks any order that still breaks it.Cart messages can be ignored
Customers can dismiss cart warnings, refresh the page, or use browser tools to bypass client-side validation. On their own, cart limits do not stop an order from going through.
Checkout is the last line of defense
When rules are enforced at checkout, orders that violate limits simply cannot complete. The "Complete Order" button blocks until the cart complies.
Server-side cannot be disabled
Shopify Functions run on Shopify servers, not in the customer browser. Disabling JavaScript or clearing cookies has no effect on them.
Built on Shopify Functions
The new standard for checkout rules
Already on the new infrastructure
If your current order limit app uses Scripts or checkout.liquid, it has stopped working. DC Order Limits is built on Shopify Functions.Shopify Scripts is retired
Shopify retired checkout.liquid and Shopify Scripts in 2026. Apps that relied on them stopped working. Checkout rules now require Shopify Functions.
Checkout extensibility is now mandatory
Shopify completed the rollout of checkout extensibility in August 2026. Only apps using Shopify Functions continue to work at checkout.
DC Order Limits uses Shopify Functions
Your order limits run on the new infrastructure. You do not need to migrate anything, and your rules will not stop working after a Shopify update.
Checkout Validation Features
What you can enforce at checkout
Every rule type works at the checkout level
Quantity Limits
Min/max per product, variant, collection, or entire cart. Checkout blocks orders exceeding limits.
Price Limits
Minimum order value for wholesale accounts. Maximum order value to prevent fraud. Both enforced at checkout.
Weight Limits
Cap total order weight for shipping cost control. Orders exceeding weight limits cannot proceed.
Customer Caps
Lifetime limits tracked across orders. Customer who hit their cap are blocked at checkout.
Mixed Cart Blocks
Prevent incompatible products in the same order. Frozen + ambient, preorder + in-stock, subscription + one-time.
Customer Tag Rules
Different limits for different customers. Wholesale gets different checkout rules than retail.
How checkout validation works
Rules run on Shopify servers, not customer browsers
Step 1: Customer adds items to cart
Cart validation shows warnings if limits are approached. This is optional guidance to improve UX.
Step 2: Customer proceeds to checkout
Shopify sends the cart to our validation function running on Shopify servers.
Step 3: Rules are checked server-side
Our Shopify Function checks all active rules against the cart contents and customer history.
Step 4: Checkout proceeds or blocks
If rules pass, checkout continues. If violated, the customer sees an error and cannot complete the order.
Use Cases
When checkout validation is critical
Scenarios where you cannot afford bypasses
High-demand releases where determined buyers will try every workaround. Checkout validation stops them.
B2B accounts must meet MOQ requirements. Checkout ensures they cannot submit underweight orders.
Staff spend caps must be enforced. Checkout blocks orders that exceed monthly allowances.
Suspicious bulk orders are blocked before payment. No need to refund after the fact.
Weight limits for carrier restrictions. Mixed cart rules for cold chain or hazmat. Checkout ensures compliance.
One-per-customer limits that cannot be gamed. Checkout is the final gate that stops repeat buyers.
FAQs
Frequently asked questions
What is the difference between cart validation and checkout validation?
Cart validation shows error messages when customers add items to the cart. Checkout validation blocks the order at the final step if rules are violated. Checkout validation is the last line of defense: customers cannot complete the purchase until the cart meets your rules.
What does "the cart does not meet the checkout validation condition" mean?
This message appears when a checkout validation rule blocks the order. A validation function running on Shopify servers checked the cart against a rule (a quantity limit, customer cap, or cart condition) and the cart failed it. As a customer, adjust the cart to meet the store rules. As a merchant, find the app rule that fired and set a custom error message so customers see exactly what to change instead of this generic text.
Can customers bypass checkout validation?
No. Checkout validation using Shopify Functions runs on Shopify servers, not in the browser. There is no way for customers to disable, modify, or bypass these rules. If the order violates a rule, checkout blocks it.
Do I need Shopify Plus for checkout validation?
No. DC Order Limits uses Shopify Functions (checkout extensibility), which works on all Shopify plans — Basic, Shopify, Advanced, and Plus. Checkout validation is not exclusive to Plus stores.
What happened to Shopify Scripts?
Shopify retired Scripts and checkout.liquid in 2026. Apps that used them stopped working at checkout. Shopify completed the move to checkout extensibility in August 2026. DC Order Limits uses Shopify Functions, so nothing changed for merchants using it.
What types of rules can I enforce at checkout?
Quantity limits (min/max per product, collection, or cart), price limits (minimum order value), weight limits, customer purchase caps (lifetime or time-based), mixed cart restrictions, and customer tag-based rules. All are enforced at checkout.
What error message do customers see?
Customers see a clear message explaining why checkout is blocked and what they need to change. You can customize messages for each rule to match your brand voice.
Does checkout validation slow down my store?
No. Shopify Functions run on Shopify infrastructure, not your theme. They execute in milliseconds and do not add page load time. Performance impact is negligible.
Learn More
Related guides
What you can enforce on Basic, Shopify, and Advanced plans vs what requires Plus.
Step-by-step setup for quantity limits, price limits, and customer caps.
Enforce rules that cannot be bypassed
Checkout validation using Shopify Functions ensures your limits are respected. Install DC Order Limits and start enforcing rules that cannot be bypassed.