---
title: >-
  Add tax validation with localizedFields in Checkout UI Extensions & Functions
  - Shopify developer changelog
description: >-
  Shopify’s developer changelog documents all changes to Shopify’s platform.
  Find the latest news and learn about new platform opportunities.
source_url:
  html: >-
    https://shopify.dev/changelog/posts/add-tax-validation-with-localizedfields-in-checkout-ui-extensions-functions
  md: >-
    https://shopify.dev/changelog/posts/add-tax-validation-with-localizedfields-in-checkout-ui-extensions-functions.md
metadata:
  effectiveApiVersion: ''
  affectedApi:
    - displayName: Admin GraphQL API
      handle: admin-graphql
    - displayName: Functions
      handle: functions-api
  primaryTag:
    displayName: API
    handle: api
  secondaryTag:
    displayName: Update
    handle: update
  indicatesActionRequired: false
  createdAt: '2025-01-06T11:54:33-05:00'
  postedAt: '2025-01-06T13:00:00-05:00'
  updatedAt: '2025-03-31T19:26:21-04:00'
  effectiveAt: '2025-01-06T13:00:00-05:00'
---

January 6, 2025

# Add tax validation with localizedFields in Checkout UI Extensions & Functions

DateJanuary 6, 2025

FlagsUpdate

SurfacesAPI

Affected APIs[Admin GraphQL API](https://shopify.dev/changelog?api_type=admin-graphql)[Functions](https://shopify.dev/changelog?api_type=functions-api)

**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](https://shopify.dev/docs/apps/build/markets/add-locally-required-order-data#validate-a-country-field).