If you are a Shopify Plus merchant, a major change is coming. Shopify has announced the deprecation of checkout.liquid, the file that has powered custom checkouts for years. In its place comes Checkout Extensibility—a more secure, faster, and upgrade-safe way to customize your checkout.

What is Checkout Extensibility?

Historically, Shopify Plus merchants customized their checkout by directly editing the checkout.liquid code. While flexible, this approach had major downsides:

• Upgrade Issues: Custom code meant you didn't get automatic updates from Shopify.
• Security Risks: Direct code access could introduce vulnerabilities.
• Performance: Poorly written scripts could slow down the checkout process.

Checkout Extensibility replaces this with a suite of app-based tools:

1. Checkout UI Extensions: For adding custom UI elements (banners, upsells, trust badges).
2. Shopify Functions: For backend logic like complex discounts, shipping rules, and payment customization.
3. Web Pixel API: For secure, non-blocking tracking and analytics.

Why You Should Migrate Now (Not Later)

1. Lightning Fast Performance

Checkout Extensibility runs on Shopify's infrastructure, not in the browser's main thread. This means your checkout loads instantly, leading to higher conversion rates.

2. One-Click Upgrades

Since you aren't hacking the core code, you automatically get every new feature Shopify releases (like the new one-page checkout) without breaking your customizations.

3. Better Conversion with Shop Pay

The new system is fully integrated with Shop Pay, ensuring a seamless experience for the millions of users who use it.

How to Migrate: A Developer's Roadmap

Migrating isn't just a "copy-paste" job. It requires rebuilding your current customizations using the new tools.

Step 1: Audit Your Current Checkout

I start by listing every customization you currently have. Do you have a "Terms and Conditions" checkbox? A post-purchase upsell? A custom shipping logic?

Step 2: Map to New Tools

• Visual Changes: Use the Checkout Editor (drag and drop).
• Custom UI: Build React-based Checkout UI Extensions.
• Logic: Write Rust or JavaScript-based Shopify Functions.
• Tracking: Move GTM and Facebook Pixel scripts to the Web Pixel API.

Step 3: Build and Test

I develop these extensions in a development environment, testing them rigorously to ensure they work under all conditions (mobile, different currencies, etc.).

Step 4: Go Live

Once tested, we publish the app to your store and switch over to the new checkout profile. The transition is seamless for your customers.

Common Migration Challenges

"I have a complex script that hides shipping methods based on tags."
Solution: We use Shopify Functions (Delivery Customization API) to handle this logic securely on the server side.

"I use a third-party app for upsells."
Solution: Check if the app has upgraded to Checkout Extensibility. If not, we might need to find a modern alternative or build a custom extension.

Need Help Migrating?

The clock is ticking on checkout.liquid. Migrating requires a deep understanding of Shopify's new development stack (React, Remix, GraphQL).

As a Shopify Developer, I specialize in these complex migrations. I can ensure your store moves to the new system smoothly, without losing data or sales.