There may come a time where you need to ensure that the postal codes entered in by your UK customers are valid. The code recipe below uses the free third-party Postcodes.io API to validate the postal code upon checkout. This code recipe could be adapted to validate for other regions.

The Code Recipe

Adding the Recipe to Your Website

You can add this recipe to your site by creating a custom plugin or using the Code Snippets plugin available for free in the WordPress repository. Read this companion article for step-by-step directions on either method.

The validation will only run if the “Billing County” on the Membership Checkout form is set to the UK.

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