What Is Checkout Extensibility? Parts and Plans

Quick Definition

Checkout Extensibility is Shopify's set of tools for changing the checkout without editing its code. It covers the blocks shoppers see, rules like discounts and delivery options, branding and tracking. Each piece plugs into a spot Shopify controls, so it keeps working when Shopify updates its checkout.

Checkout Extensibility replaced checkout.liquid, a code file only Plus stores could edit. Custom code there could break when Shopify updated its checkout. Now apps and settings make the changes, and Shopify keeps control of the page.

What Checkout Extensibility Is Made Of

Each part has its own job:

Part	What it does
Checkout UI extensions	Add blocks shoppers see, like an upsell, a trust badge or a gift note box. See checkout UI extension.
Shopify Functions	Run rules behind the scenes, like hiding a payment option or applying a Shopify discount function.
Branding	Sets the colors, fonts and logo your checkout shows.
Pixels	Track shopper actions, like starting checkout or paying, for analytics and ad tools.
Post-purchase extensions	Add one page after payment and before the Thank you page. See post-purchase checkout extensions.

Example: moving three old checkout hacks

Say a Plus store's old checkout had three custom hacks. They added a gift message box, hid cash on delivery for orders over $300 and loaded an ad tracking tag.

The gift message box becomes an app's checkout UI extension you drag into place in the checkout editor.
Hiding cash on delivery turns into a payment rule from an app built on Shopify Functions.
The tracking tag becomes a pixel under Settings, then Customer events.

Nobody edits checkout code. Each piece is built to survive Shopify's checkout updates.

Why Checkout Changes Carry So Much Weight

In our visitor data from 958 stores, about 57% of shoppers who start checkout go on to buy. Anything you add here sits in front of people close to paying, and it can help them finish or get in the way.

Checkout Extensibility sets what you can add. What's worth adding is a bigger question, and our guide to Shopify checkout optimization covers it.

Myth: Checkout Extensibility Is Only for Shopify Plus

Shopify Plus stores get the most room, since only they can add blocks inside the information, shipping and payment steps. Any plan can add blocks to the Thank you and Order status pages. Branding, pixels and App Store apps built on Functions work on any plan too. You place blocks and set branding in the checkout editor, under Settings, then Checkout.

Our app, Growth Suite, uses these tools. On Plus stores it adds a checkout offer progress bar and checkout upsells. Its Volume Discount feature runs on a Shopify discount function.