Rulestage runs minimum and maximum quantity, order value, per-customer limit, capacity and signed-in-customer rules inside Shopify's checkout validation. Before you publish, run any cart, buyer and country through the simulator and see which rule wins. Contradictory rules block publishing. Every publish is a version you can roll back. Saved scenarios show what a change would do. When a shopper reports a block, load that cart against the version that was live and read the reason.

• Simulator runs your draft rules on any cart, buyer and country
• Per-customer, by-country and by-product purchase limits
• Contradictory or unreachable rules block publishing until fixed
• Every publish is a version; rollback publishes it again, never rewrites
• Enforced server-side in Shopify checkout validation, no theme script