King Checkout Validation

This app really saved us. We have an integration with SAP, and some fields have character limits that can’t be changed. This app solved that issue, and we also used it to block sending orders to certain islands via ZIP code rules — which works perfectly. I highly recommend this app. We’re running it on eight stores now.

This is a fantastic product and the developer is extremely responsive and helpful! Great app!

Very nice app - and especially very good and fast support. Thanks.

Danke für die Hilfe vom Support, macht bis jetzt einen guten Eindruck. :)

The app does its job smoothly and the support team is very quick to answer inquires and to fix issues. Gordon was a great help with the problems we have encountered.

Very good app for checkout validation, and the support team is very responsive.

Created a new functionality, the day after reaching out on chat for advise on how to setup a feature, and testing the initial solution.

Great app for controlling the checkout process with custom rules! We mainly use it to block specific ZIP codes and set character limits in fields before the data gets pushed to Shopify — and it works exactly as needed.

What really stands out is the support team. When we first ran into an issue with ZIP code blocking, they quickly developed a new feature that supports both prefix and suffix rules. Later, when we needed to block something else, they genuinely tried to help — even though it turned out to be a limitation on Shopify’s side, not theirs.

Highly recommended if you need more control over your checkout fields and top-notch support behind it.

He is an exceptional developer—truly the best. When it came to the new Shopify field, he resolved it immediately. His expertise and efficiency are truly remarkable.

Once again, I would like to express my deepest gratitude for your support and dedication. Your contributions have been invaluable, and I hold your work in the highest regard.

Great app and best support!