Create a Checkout Validation Rule

Checkout validation rules let you block customers from completing checkout when specific conditions are met. Show a custom error message at the top of the checkout page or under a specific field.

How to Create a Checkout Validation Rule

  1. From the dashboard, click Create rule.
  2. Select Checkout validation.
  3. Fill in the rule settings (explained below).
  4. Click Save.

Rule Settings

Rule Name

Enter a descriptive name for internal reference. Customers never see this.

Rule Status

Choose Test, Active, or Inactive. See Understanding Rule Status.

Error Message

Enter the message customers see when the rule triggers. This message explains why checkout is blocked.

  • Maximum length: 255 characters (a character counter is shown as you type).
  • This field is required — you must write your own message.
  • Write a clear, helpful message so customers understand what to fix.

Good examples:

  • “Minimum order value is $25. Please add more items to your cart.”
  • “We cannot ship to PO Box addresses. Please enter a street address.”
  • “Phone number must include a valid country code.”

Avoid:

  • Vague messages like “Error” or “Invalid order.”
  • Technical language customers won’t understand.

Error Position

Choose where the error message appears at checkout:

Top of page:

  • Top of the checkout page — shows as a banner at the top of checkout

Under a specific field:

  • Contact (Email/Mobile phone number)
  • Address (line 1)
  • Address (apartment, suite, etc)
  • City
  • Company
  • Country Code
  • First name
  • Last name
  • Phone Address
  • Province / State
  • Zip / Postal code

Tip: Match the error position to the relevant field. If your rule validates the zip code, place the error under “Zip / Postal code” so the customer knows exactly what to fix. Use “Top of the checkout page” for general validations not tied to a specific field (e.g., minimum order value).

Validation Trigger (Conditions)

This is where you define when checkout should be blocked:

  • Always — blocks every checkout (rarely useful on its own).
  • On condition — blocks checkout only when your conditions are met.

Most validation rules use On condition. The conditions define who gets blocked — for example, customers with a cart total under $25, or customers with a PO Box address.

Common Examples

Minimum order value:

  • Error message: “Minimum order is $25. Please add more items.”
  • Error position: Top of the checkout page
  • Condition: Order subtotal → Is less than → 25

Block PO Box addresses:

  • Error message: “We cannot ship to PO Box addresses. Please enter a street address.”
  • Error position: Address (line 1)
  • Condition: P.O. box address (boolean — no value needed)

Require specific country:

  • Error message: “We currently only ship within the United States.”
  • Error position: Country Code
  • Condition: Country → Not equals to → United States

Block orders with too many of one product:

  • Error message: “Maximum 5 units per product. Please adjust your cart.”
  • Error position: Top of the checkout page
  • Condition: Product quantity → Is greater than → 5

Templates

When you select Checkout validation from the rule type grid, you may see a template selection modal. Templates are pre-built validation rules for common scenarios (like fraud prevention or minimum order value). You can:

  • Select a template to pre-fill the rule with suggested conditions, error messages, and positions.
  • Create custom to start with a blank rule.

Templates are a starting point — you can always modify any field after selecting one.

Good to Know

  • Validation rules block checkout completely. When a rule triggers, the customer sees the error message and cannot proceed until the condition is no longer met (e.g., they change their address or add more items).
  • Test before activating. A misconfigured validation rule could block all customers from checking out. Always use Test mode first with test@testing.com.
  • Error messages should be actionable. Tell customers what to do to fix the issue, not just that there is one.
  • Multiple validation rules can run at the same time. If several rules trigger, the customer sees multiple error messages.