Restricted carts
Stop checkout when products, variants, SKUs, tags, or cart combinations should not be purchased together.
Shipped · Checkout validation
Block unwanted Shopify checkouts before payment
Create checkout rules for cart contents, quantities, customer tags, shipping details, discounts, and order context. When a cart breaks your rule, BlockCart stops checkout and shows the shopper a clear message.
Block checkout before payment
Build rules around cart, customer, shipping, and discount data
Show customers a clear message when rules match
The problem
Some orders should never reach payment
Restricted products, invalid cart combinations, wholesale limits, PO boxes, and edge-case discounts create manual cleanup after checkout. BlockCart moves those guardrails earlier, before the order becomes an operational problem.
Use cases
Common checkout rules merchants create
Quantity and order limits
Enforce minimums, maximums, pack sizes, or wholesale buying rules before the customer pays.
Customer-specific guardrails
Apply rules to tagged customers, logged-out shoppers, B2B buyers, or merchants with special account logic.
Address and shipping checks
Block scenarios tied to countries, postal codes, shipping choices, or other checkout details.
Setup
How BlockCart works
01
Create a rule
Name the checkout rule and decide when it should run.
02
Choose conditions
Combine cart, product, customer, discount, shipping, and order context checks.
03
Write the message
Tell shoppers exactly what needs to change before they can continue.
04
Review and sync
Keep rules easy to audit while Shopify handles the checkout validation.
Objections
BlockCart questions merchants ask
Can native Shopify settings do this? +
Native settings cover some broad checkout restrictions, but they are limited when rules depend on specific cart, customer, product, discount, or address conditions.
Do I need to edit my theme? +
No. BlockCart is built around Shopify checkout validation, so merchants can add guardrails without theme workarounds.
What does the shopper see? +
When a matching rule blocks checkout, the shopper sees the message you wrote so they know what to fix.
Ready to add checkout guardrails?
Start with one rule: the cart scenario you most want to stop before payment.
Create your first cart block