Enable Shopify Checkout Validation

Cart Reserve uses Shopify's checkout rules (a built-in Shopify feature) to enforce reserved quantities during checkout.

This step ensures that customers cannot complete checkout with quantities that exceed their active reservation or allowed limits.

Why This Step Is Required

This step prevents customers from buying more items than their reservation allows.

Without it, customers could bypass reservation limits at checkout by editing quantities or using multiple tabs.

It also protects reserved products against shoppers who try to skip the reservation system entirely — for example by disabling the app in their browser. Anyone reaching checkout with a reserved product but no valid reservation is stopped and asked to reserve it first. See Limits and Security for details.

How to Enable Checkout Validation

1. Open Shopify Admin
2. Go to Settings → Checkout
3. Navigate to the Checkout Rules section
4. Locate cart-checkout-validation
5. Click Turn on
6. Save your changes

Once enabled, Cart Reserve will automatically validate reserved quantities during checkout.

Verification

Checkout validation is enabled when:

• The cart-checkout-validation rule is active in Shopify settings
• Checkout blocks quantities that exceed active reservations

If checkout validation is not enabled, Cart Reserve will not prevent invalid checkout attempts.

Next Step

Continue with Enable App Embed to connect Cart Reserve to your storefront.