Checkout app extensions

Checkout app extensions make it easy for developers to extend their app code into checkout, and customize many aspects of the checkout experience.

There are two types of checkout app extensions available: UI extensions and Scripts. The first UI extension point to be released to developers is the post-purchase extension.

Post-purchase extensions

Post-purchase extensions allow you to add new UI and functionality to the post-purchase page, and are built into apps using extension points, APIs, and UI components provided by Shopify.

Extension points

  • Extension points API - Learn about the APIs provided to the post-purchase extension points.
  • Components - Learn about the components you can use to build post-purchase experiences.
  • JWT specification - Learn how JWTs (JSON web token) need to be structured in order to be used in post-purchase app extensions on the Shopify checkout.


Scripts let you add custom server-side logic to checkout, and securely change the behavior of payment methods, shipping rates, and checkout line items.

Scripts APIs reference documentation

Read the complete reference documentation for the Scripts APIs:

Next steps