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Zen Cart Valid Cart

Zen Cart Valid Cart

A Zen Cart™ mod which allows you to specify conditions under which customers may not check out.

Relevance: Zen Cart™ 1.3.6 - 1.3.9, 1.5.x

Cost: Starting at $300 installed, more for very complex validations. This is not a plugin; it's custom software developed for your needs to your specifications.

Support Thread: My commercial software is not supported on the Zen Cart forum. Please email me questions instead.

See it Live: Go to my demo shop and add an item costing less than $100 to your cart. You will immediately see an error message on the shopping cart page and on the shipping page because the validation "shippable total must be greater than $100" was used.

Want something similar for your store? Great! Contact me with your requirements. Let's get started!


This mod permits you to set preconditions on the checkout process. Any rule which is appropriate for your business may be implemented as a validity check. Some sample rules are:
  • If good from category <x> are purchased, goods from category <y> must be purchased.
  • A minimum number of goods from one particular category or group of categories must be purchased.
  • If any goods from category <x> are purchased, a minimum number must be purchased.
  • Validations requiring groupings of goods from top level categories and subcategories
  • Only customers from certain countries may purchase certain products (or any products)

Note: The example in my demo cart is a trivial case. If your requirement is simply "Over $X must be spent in order to checkout," you may use the Minimum Order Contribution. Valid Cart is designed to do more complex validations.

Invalid Shopping Cart Page

Zen Cart Shopping cart page that has failed validation

On the Shopping Cart page, the message is displayed in the error style, and the checkout button is hidden. Again, your customers cannot checkout until they resolve the problem.

Navigating to the checkout page by typing a URL or using a checkout link in the header or footer will result in redirection back to the shopping cart page. If you prefer, an error message on the checkout shipping page (with payment buttons disabled) may be displayed.

Here's a recent example I did for a client:
Zen Cart Valid Cart enforcing rules

When an item from the first column (ProCase) was in the cart, the cart also had to contain one of the items from columns 3-6. Otherwise, a message would be displayed, and checkout would be blocked.

This rule was needed because the products in the first column were considered "Add-On" products.

I charge a fee starting at $300 for Valid Cart depending on the complexity of your validations. Please contact me with your requirements for details.