Add tax validation with localizedFields in Checkout UI Extensions & Functions

As of Jan 6, 2025, you can use the new localizedFields in the Checkout UI Extension API and Function API to implement custom validation for tax fields in checkout. The localizationExtensions field in the Admin GraphQL API has now been renamed to localizedFields too. Additionally, you can now target tax fields in checkout for error messages.

Available currently in the unstable API version and will be released to the stable 2025-01 API version. Learn more on how to implement localizedFields.