How to create a Shopify custom checkout with Shopify Functions and Checkout Extensibility


Chris Rausch


September 21, 2023

Shopify has provided store owners with more tools than ever to build a custom and effective checkout process that minimizes abandoned carts and improves customer experiences. Two essential tools include Checkout Extensibility, the new checkout system, and Shopify Functions, the best way to customize checkout functionality.

If you want the best checkout possible, you’ll need to use both correct – here’s how.

Checkout Extensibility: Shopify’s highly customizable checkout upgrade

shopify checkout extensibility

Checkout Extensibility is the new checkout system that’s replacing checkout.liquid for all Shopify stores by August 14, 2024. It’s similar in function to checkout.liquid because they both contain the code required to generate, display, and interact with the checkout process for your Shopify store. However, Checkout Extensibility adds a number of convenient benefits.

Checkout Extensibility is an app-based system. It lets you install checkout extensions that extend what you can do when customizing the look and feel of your checkout page, such as upselling apps or checkout field customization apps. Previously, you would have to directly edit the checkout.liquid file to make changes, which came with the risk of breaking your checkout. Now, each change is self-contained in an app that won’t break the checkout page when updates happen or if someone makes a mistake in copying code over for customizations.

There are also new customization options available for checkout through the branding API. This feature allows you to make advanced changes to the way your checkout page looks, including creating profiles that allow you to easily change between styles for easy A/B testing. You can change text colors, fonts, banner sizes, checkout fields, and much more through code or with checkout extensions.

Shopify Functions: access to backend data like never before

Shopify Functions, the successor of Shopify Scripts, is a result of the upgrade to Checkout Extensibility that lets you use apps to make functional changes to your checkout process with ease. The previous system required direct changes to code that opened your checkout up to problems and failure that could lose you business. However, Shopify Functions employs Checkout Extensibility’s same app-based approach to minimize the risk of problems arising, including allowing the apps to be reused in any store without specific changes.

With Shopify Functions, the backend of Shopify’s checkout system is unlocked so that you can interact with it and make changes that improve your checkout process. Customer profiles, locations, cart contents, prices, and many other data points can be used to create a variety of different changes through the Shopify Functions API.

7 customizations you can make with Checkout Extensibility and Shopify Functions

shopify functions checkout customizatons

The possibilities are basically endless when you combine Checkout Extensibility and Shopify Functions. Here are seven ways you can build a better checkout with the tools these features provide.

Customizing checkout fields

Checkout fields are where customers spend the most time when completing their orders. If you can limit the amount of information required from them, you’re more likely to secure conversions by shortening checkout times.

Checkout Extensibility lets you remove and edit checkout fields so that you only ask for essential information. Or, you can add new fields like a customer note section to help coordinate deliveries or collect important information without needing to follow up with the customer afterward.

Implementing custom discounts

Shopify allows you to create simple discount codes and offers at checkout, but they’re limited in their complexity. If you want to do more than offer 5% off with a promotional code, Shopify Functions can help.

By accessing cart data, you can use Shopify Functions to provide discounts based on the items purchased, subtotal of the cart, or number of items purchased. You can deduct $50 when their cart reaches $500 or add discounts to allow for build-your-own bundles with multiple product types.

Adding trust elements

Trust is an essential element of online sales. If your customers don’t believe that you’re the right company for them or don’t trust your sales process, you risk losing out on a sale.

With Checkout Extensibility, you can add custom elements to your checkout page to build confidence. Testimonials, reviews, security badges, and guarantees you offer are just a few ways to prevent your customers from second-guessing themselves once they reach the end of your funnel.

Editing shipping and payment methods

You have plenty of reasons to want to control shipping and payment methods in your store. Local delivery is a great option to offer, but showing it to customers outside of your range is misleading. Certain payment methods may also have limitations in certain countries for international sales, or you might just want to offer cash payment for certain local orders.

Shopify Functions allows you to check the customer’s address to see if they are in range for local payment and shipping options. If not, they won’t display them. The same is true for payment options for international customers based on the country they choose at checkout.

Including FAQs

It’s hard to answer all of the potential questions a customer could have that are preventing them from completing checkout. However, you can do your best by adding essential FAQs to your checkout page to prevent them from leaving to find answers.

Use Checkout Extensibility to add elements, including FAQs about processing times, return policies, guarantees, and any other questions that a customer might want to know before completing their order.

Validating carts and checkout information

Sometimes, you want to limit who can buy from your store, what they can buy, and how many items are allowed. Information like purchase history, location, or cart contents can be used to avoid refunded orders and protect yourself from high-risk transactions.

Shopify Functions lets you create rules that disallow checkout under certain conditions that you set. Limiting new customers to $500, limiting customers to 1 item per purchase for new releases, and preventing international orders are just a few ways you can use the cart and checkout information to take control over your checkout.

Adding upsells and cross-sells

Upsells and cross-sells are offers that you make to customers to increase average order values in your store. Using Shopify upsell apps like UpsellPlus lets you build custom offers that include BOGO, complementary products, and item upgrades at a discount so that customers spend more money.

UpsellPlus works with Checkout Extensibility to grow your revenue and AOV - and it comes with a 7-day free trial.

Checkout Extensions Plus: Use Checkout Extensibility and Shopify Functions with ease

If you’re looking to make customizations to your Checkout Extensibility checkout page, look no further than Checkout Extensions Plus.

Checkout Extensions Plus allows you to utilize Checkout Extensibility along with Shopify Functions to make changes to the look, feel, and function of your checkout process. Customize checkout fields, add elements, change the look of anything, build custom discounts, show or hide certain shipping and payment options, and much more with a simple, code-free interface.

Get started today with a 7-day free trial.

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