Gil Greenberg is the founder and solo developer of Checkout Blocks, the popular all-in-one checkout customization app.

From the get go, Checkout Blocks leveraged Checkout Extensibility and its suite of APIs, UI components, and branding capabilities to allow merchants to make no-code customizations like upsells and custom content in their checkout. As it grew in popularity to serve more merchants around the world, Gil then looked to metaobjects to manage custom data with added security, privacy, and performance. While Shopify’s platform handled the complexities of hosting, scaling, and tooling, Gil was able to focus on what he does best, solving merchant needs.

Gil’s early adoption of Checkout Extensibility on Shopify’s platform proved to generate compounding returns. Checkout Blocks is one of Shopify’s most popular checkout apps. Within the last year, the app secured its position in the top 3 during Black Friday Cyber Monday, received the “Built for Shopify” designation, and has earned adoration with 5-star reviews.

The inception of Checkout Blocks

During Shopify’s Summer ’22 Edition, Gil learned about Checkout Extensibility, the new way of customizing the Shopify Checkout that’s app-based, upgrade safe, and more performant than checkout.liquid. With two years of experience building post-purchase extensions, he saw the opportunity immediately. Shopify is providing the tools and integrations to extend the benefit of no-code checkout customization to merchants with an app-based model. This makes customizations as easy as installing, configuring, and launching an app. Gil launched Checkout Blocks just months later, becoming one of the first extensibility apps available.

As Shopify continued to launch new Checkout Extensibility capabilities and APIs, Checkout Blocks expanded its feature set as well. Today, the app enables a rich set of customizations for upsells, custom content, delivery methods, address validation, and so much more.

Checkout Blocks working within the Shopify Checkout

Going all in on Shopify’s Platform

Checkout Blocks was built entirely using platform capabilities such as Checkout UI Extensions, Branding API, Shopify Functions, and metaobjects. This eliminated the usual complexities of hosting and scaling. With Checkout Extensibility, Gil only needed to focus on the core Javascript logic knowing that customizations will look and perform consistently across Shopify stores while having full compatibility with Shop Pay. Leveraging these platform capabilities also supported Checkout Blocks with predictable and reliable performance. This ensured that customizations do not compromise user experience or checkout loading speeds.

“The model of Checkout Extensibility solves many of the technical challenges, allowing a solo developer like myself to move more quickly in solving actual problems and letting Shopify handle much of the underlying complexity (hosting, scaling, UX). By not focusing on infrastructure, I can focus strictly on solving complex customer requirements” Gil says.

Checkout Extensibility enabled Gil to deliver a reliable and upgrade safe experience to merchants. The extension APIs are versioned and follow Shopify’s standard release process and upgrade cycle. Each stable version is supported for a minimum of 12 months. Customizations made with Checkout Extensibility are also forward compatible with new capabilities and features of Shopify Checkout. In the case of the highly-requested one-page checkout feature, Checkout Blocks customizations continued to work seamlessly for merchants that switched from their existing three-page layout. When Shopify introduced Checkout Extensibility to new surfaces like the Thank you and Order status pages, forward compatibility meant that Gil’s extensions continued to work as well.

Checkout Blocks on the Thank you and Order Status pages

“A key benefit of extensibility-powered checkout is safe and hassle-free upgrades. Unlike checkout.liquid customizations which are bespoke and often break, requiring continuous upkeep” Gil says.

All of this was not possible before with solutions like checkout.liquid and Additional Scripts on the Thank you page.

Scaling with Custom Data

As Gil continued to expand the user base of Checkout Blocks, he sought to increase app performance, reduce load times, and decrease API calls. Checkout Blocks loaded slower in geographies furthest from Gil’s external database that hosted his app configuration, a challenge he wanted to address. Gil looked to metaobjects, which provided a flexible way to store and manage custom data such as user settings and app configurations within Shopify’s infrastructure. Metaobjects provided managed hosting, reliable performance, global distribution, and further simplified the upkeep of Checkout Blocks.

Since migrating his app data storage to metaobjects, Gil has reduced Checkout Blocks’ global server traffic by 90% and server cost savings by 85%. This also improved load times for the checkout app blocks powered by his app while serving a growing merchant base. For Gil’s merchants, this meant faster speeds, higher conversions, and more upsells from their checkout customizations.

“By moving that infrastructure to Shopify, I am creating less cost on the developer side because I no longer have to maintain a complex setup to performantly load things in checkout” Gil says.

The overall app development experience has improved as well. While metaobjects took some upfront planning to use effectively as a replacement to his old data structures, Shopify’s tooling and infrastructure made it possible for a single developer to accomplish tasks that used to require a team.

Looking ahead

Checkout Blocks has been adopted by hundreds of top merchants across 46 countries, scaled revenue by 50x, and continues to expand its capabilities while supporting new surfaces like the Thank you and Order status pages. Gil’s experience as a solo developer demonstrates the power of using the Shopify platform to accelerate development and reach a wide audience of merchants.

“In 2024, many brands are looking for Checkout Extensibility solutions and if an app is not yet running on extensibility, it will more likely be skipped over. Look at extensibility as a net positive for the merchant experience due to increased scalability and better customer security” says Gil.

Shopify’s platform continues to get better at a rapid pace. Shopify recently released 14 new APIs and UI components for Checkout Extensibility in the Shopify Winter '24 Edition. Gil encourages the developer community to lean in. Now is the time to migrate existing checkout.liquid customizations or start building. The existing way to customize the Shopify checkout with checkout.liquid is deprecated and will be turned off in stages

August 13, 2024: Checkout.liquid customizations for the Information, Shipping, and Payment pages of checkout will be turned off.
August 28, 2025: Checkout.liquid customizations and apps using script tags and additional scripts for the Thank you and Order status pages will be turned off. Shopify Scripts will continue to work alongside Checkout Extensibility, including Shopify Functions, until this date.

Visit the Shopify developer documentation to learn more

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Sharon Shi