Installation – Checkout Page

To enable VAT number validation in the checkout, you need to customize the Checkout page of your Shopify Plus store using Checkout UI Extensions.

Follow the steps below to add the EU VAT Validation block to the correct location in checkout.

Step-by-step installation

1. Open Checkout customization

In your Shopify admin:

1. Go to Settings → Checkout

2. Under Configurations, click Customize next to the checkout profile you want to edit

This opens the Shopify Checkout Editor.

2. Add the EU VAT Validation app block

In the checkout editor:

1. Click Add app block

2. Select EU VAT Validation

3. Enable Allow app to block checkout

⚠️ Important
Enabling Allow app to block checkout ensures that VAT numbers are validated before checkout completion.

3. Save and publish

Click Save to apply the changes.

The VAT number field is now enabled in checkout.

Where to place the app block

The correct placement depends on your checkout layout and product type.

One-page checkout layout (physical goods)

If your store uses one-page checkout and sells physical products:

• Place the app block in the Delivery section

• Inside Delivery address

This ensures the VAT field is shown alongside address details.

Three-page checkout layout (physical goods)

If your store uses three-page checkout:

• Place the app block on the Information page

• In the Contact section

• Inside Shipping address

Selling digital goods (or mixed carts)

When selling digital products, customers purchasing only digital items do not see shipping fields in checkout.
They are only asked for billing information.

To ensure VAT validation is always available, you must add a second app block.

One-page checkout – digital goods

Add an additional EU VAT Validation app block:

• In the Payment section

• Just below the Remember me block

Three-page checkout – digital goods

Add an additional EU VAT Validation app block:

• On the Information page

• In the Contact section

• Just below the Shipping group

Business customers & address fields

For B2B customers, the VAT number field should not be embedded directly inside address input fields.

Best practice:

• Place the VAT validation block outside the address input group

• This avoids conflicts with:

  • Company address validation

  • Billing vs shipping logic

  • Shopify B2B company profiles

The placements described above already follow this best practice.

Final verification

After installation, test the setup:

1. Start a checkout

2. Use an EU address

3. Enter a valid EU VAT number

4. Confirm:

   • VAT is validated successfully

   • VAT is removed immediately

   • Checkout cannot be completed without validation (if blocking is enabled)

Summary

• One-page and three-page checkout require different placement

• Digital goods require an additional app block

• VAT validation must be placed outside address input fields for B2B

• Always enable Allow app to block checkout if validation is required