Checkout Extensibility

Shopify Checkout Extensibility: what changed, what broke, and what to do if your customisations died.

Shopify retired checkout.liquid, the editable checkout template, in two stages: August 2024 for the information, shipping and payment pages and August 2025 for the thank-you and order-status pages. Everything built by editing that template stopped working. Checkout Extensibility is the replacement: apps and extensions in defined slots, Functions for logic, branding through an API. Here is what it can do, what it cannot, and the options for the features that fell through the gap.

See pricing → How it works →

What Checkout Extensibility consists of

Checkout UI extensions. App-provided blocks placed in fixed slots: banners, custom fields, upsell offers, trust content. Payment-step slots are Plus-only.
Shopify Functions. Server-side logic for discounts, delivery and payment customisation, cart validation and cart transforms, installed from apps or, on Plus, written by you.
Branding API and checkout editor. Colours, type, layout options within Shopify's structure.
Web pixels. Sandboxed tracking that replaces scripts injected into the old template.
Post-purchase extensions. One-click offers after payment.

What broke when checkout.liquid went

Custom scripts on the checkout: tracking, chat widgets, fraud tools, affiliate pixels not rebuilt as web pixels.
Injected markup: custom fields, notices, upsells and trust badges placed by editing the template.
Layout changes and reordered sections.
Payment-step tweaks and gateway-specific hacks.
Any app that depended on template access rather than the extension framework.

Many merchants only noticed when a conversion pixel silently stopped firing or an upsell app went blank.

Migrating what can be migrated

Tracking moves to web pixels, either Shopify's built-in Meta, Google and TikTok integrations or a custom pixel. Verify with test orders; sandboxed pixels lose some data compared to the old scripts, which is why server-side events matter more now.
Custom fields, banners and trust content move to checkout UI extensions through an app. On non-Plus plans they can sit on the thank-you and order-status pages; on Plus, on the checkout steps too.
Discount, shipping and payment rules move to Functions via apps.
Post-purchase upsells move to post-purchase extensions.

What cannot be migrated on any plan

A different layout or step order.
A gateway Shopify does not list, or failover between two gateways.
Charging in the buyer's currency without Shopify Payments.
Full control of page weight and scripts.
In-checkout order bumps on non-Plus plans.

If your lost feature is on this list, rebuilding it inside Shopify's checkout is not possible. The alternative is a checkout you control that writes orders back into Shopify. Custom checkout versus native, compared.

The custom checkout route

CascadeCheckout hosts a single-page checkout on a subdomain of your brand. It reads carts, shipping rates and discounts from Shopify, presents your branding, runs bumps and one-click upsells, fires client and server-side tracking, captures through any gateway with an API, and writes the paid order into Shopify with full detail. It is not affected by Shopify's checkout roadmap because it does not run inside Shopify's checkout. Merchants who lost the most in the checkout.liquid retirement, high-risk and cross-border stores with custom payment handling, are the ones most often moving to it. How it works.

Frequent questions

What is Shopify Checkout Extensibility?

Shopify's framework for customising checkout through app extensions, Functions, a branding API and web pixels, replacing direct edits to the checkout.liquid template.

When was checkout.liquid deprecated?

August 2024 for the information, shipping and payment pages, and August 2025 for the thank-you and order-status pages.

Do I need Shopify Plus for Checkout Extensibility?

Basic branding, post-purchase offers, thank-you page blocks and app-provided Functions work on all plans. Extensions on the checkout steps themselves and custom Functions are Plus-only.

My checkout customisations stopped working. What now?

Rebuild them as extensions and pixels where the framework allows. For layout, gateway and currency changes it does not allow, use a checkout on your own domain that writes orders back into Shopify.

Bring your store URL and the gateway that already said yes.

Live in 24-48 hours. Founder-answered support on WhatsApp.

See pricing →

Checkout customization without Plus → · Checkout upsells → · Own-domain checkout → · Meta CAPI on a checkout subdomain →

CascadeCheckout is checkout software, not a payment service provider, bank or merchant-account seller. You contract with your own gateway or acquirer, disclose your real business category to them, and receive payouts from them. We never hold funds and we do not promise that any processor will approve you.