By Cristian Daron
Shopify has retired checkout.liquid: the last deadline, for stores on non-Plus plans to upgrade their Thank you and Order status pages, was August 26, 2026. If your store relied on checkout.liquid for trust badges, upsell offers, custom fields or branding, those now have to live in Checkout Extensibility. Here's the migration playbook I use with clients.
What Changed and Why It Matters
Shopify's Checkout Extensibility is the new standard for customizing checkout without editing checkout.liquid directly. It uses UI Extensions (React-based components) built in the Checkout UI Extensions framework, and the Checkout Branding API for visual customization. The old way required Plus and direct template editing, the new way is app-based and works at more plan levels.
Auditing Your Current Checkout Customizations
Before migrating, document everything you've customized. Common checkout.liquid customizations I find: custom trust badge HTML, countdown timers, custom field additions (gift message, delivery date), loyalty points display, upsell banners, and custom CSS for branding. Each needs a Checkout Extensibility equivalent.
Replacing Trust Badges and Custom Content
Use the Checkout UI Extensions API to create Banner and Text components in the purchase.checkout.block.render extension point. For trust badges: create a React extension that renders custom HTML/SVG with your trust icons in the checkout flow. Deploy via a custom Shopify app or a trusted Checkout Extensibility app like Essential Apps.
Custom Fields (Gift Messages, Delivery Notes)
Checkout UI Extensions support custom fields via the useApplyAttributeChange hook. This writes customer-entered data directly to the order's attributes, accessible in your fulfillment workflow, email notifications, and order exports. I implement this with a single-file extension, deployed in under an hour.
Post-Purchase Upsell Integration
Post-purchase extensions are the most powerful feature of Checkout Extensibility. The purchase.thank-you.block.render extension point lets you insert offers on the thank-you page. Combined with a one-click upsell app (ReConvert, Checkout Champ), you can maintain AOV lifts without checkout.liquid.
Branding with the Checkout Branding API
The Checkout Branding API (GraphQL) lets you customize colors, fonts, corner radius, spacing, and logo, all without touching template code. I configure this via the Admin API and store the settings as version-controlled JSON. It covers most of the visual customizations that used to need checkout.liquid CSS.
Testing and Conversion Rate Protection
Run both checkouts in parallel before cutting over. Use Shopify's draft checkout feature to QA every step. Key things to validate: payment methods all render correctly, discounts apply properly, custom fields save to order attributes, post-purchase extensions fire after payment confirmation, and mobile layout matches desktop. Never cut over without 48 hours of A/B comparison data.