Speed up migrating your checkout and customer account UI extensions to Polaris web components with the Shopify AI Toolkit

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Hey folks,

I’m excited to share something my team and I have been heads-down on: the Shopify AI Toolkit can now help upgrade your checkout and customer account UI extensions to Polaris web components. This tool is going to do a lot of the heavy lifting for you, from handling the React to Preact conversion, swapping legacy components with web components, to updating extension APIs.

We have enhanced the migration guides with more detailed component prop migration notes that are now indexed by the Shopify AI Toolkit. Before putting this tooling in your hands, we spent time stress-testing it internally by using the skills to migrate a number of our own first party checkout and customer account extensions and fixing the rough edges we hit along the way. We’re genuinely happy with where it landed.

Why make the jump? Extensions built with Polaris web components render significantly faster than legacy React extensions. Adopting Polaris web components also means you’re no longer locked into React, can easily share UI component code across surfaces, and ship leaner bundles that ensure faster loading time and optimal extension performance. Now with the help of Shopify AI Toolkit, your migration effort can go from hours of tedious work to several minutes, depending on the size of your extension.

How to use it

  1. Install the Shopify AI Toolkit for your preferred AI coding agent
  2. Point it at an extension and prompt either the shopify polaris checkout extensions skill or the shopify polaris customer account extensions skill to upgrade to the latest API version
  3. Review the changes your agent makes against the dev docs and run and test your extension locally before you publish:

Important note on timing

All API versions 2025-10 and later now use Polaris web components by default. As a reminder, the Shopify CLI blocks apps from being updated if any of their extensions are on an API version that is more than 1 year old. By October 1, 2026, any app that contains checkout and customer account UI extensions on API versions 2025-07 or older will be unable to be updated. Regularly update all your extensions now to avoid this restriction (More details)

Your real-world usage is the best test there is. Try it on any of your checkout and/or customer account extensions and let us know what upgraded cleanly, what needed a manual fix, where the agent got tripped up, or anything you wish it did differently. Your feedback will help us improve the AI Toolkit and docs even further.

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