Unleash the Customization Power of Shopify Functions in 2023

Unleash the Customization Power of Shopify Functions in 2023

Table of Contents

  1. Introduction
  2. Background on Functions
  3. Key Differences Between Functions and Scripts
  4. What's New in 2023
  5. Getting Started with Writing Functions
  6. Use Cases for Shopify Functions
  7. Performance Benefits of Functions
  8. Language Support for Functions
  9. Integration with the Shopify Admin Dashboard
  10. Migration from Shopify Scripts to Functions


In this article, we will explore Shopify functions and how they can be used to customize and extend the backend logic of your Shopify store. We will discuss the key differences between functions and Shopify scripts, as well as the new features introduced in 2023. Additionally, we will provide a step-by-step guide on getting started with writing functions using JavaScript. We will also explore various use cases for Shopify functions and the performance benefits they offer. Furthermore, we will discuss the language support available for functions and their seamless integration with the Shopify admin dashboard. Lastly, we will touch upon the process of migrating from Shopify scripts to functions. So, let's dive in and discover how Shopify functions can enhance the functionality of your online store.

Background on Functions

Before we delve into the world of Shopify functions, let's take a quick refresher on what functions are and their purpose. Functions were introduced as a new way for developers to write their own customized backend logic. Traditionally, developers could work on the front end using themes, Liquid, and HTML, while the database was accessible via the API. The backend logic, however, was locked up and couldn't be easily modified or extended. Shopify functions changed that by allowing developers to directly customize or extend specific parts of Shopify's backend logic.

This opens up a world of possibilities for building custom features and implementing more extensive functionality without the need for third-party apps. Functions give merchants the ability to automate processes, apply discounts, rearrange payment methods, and customize the checkout process according to their specific business requirements.

Key Differences Between Functions and Scripts

One of the primary distinctions between Shopify functions and scripts is their availability and accessibility. Shopify scripts were only available to Shopify Plus merchants, while functions are accessible to all merchants on any plan. This means that regardless of the plan you are on, you can now leverage the power of functions to enhance your store's functionality.

Performance is another major difference between functions and scripts. Functions execute approximately 100 times faster than scripts. This performance boost is crucial, especially during peak traffic periods or flash sales, where every millisecond counts. With faster execution times, functions enable a smoother and more responsive shopping experience for customers.

Language support is also a significant improvement with functions. Shopify scripts could only be written in Ruby, limiting developers to a single programming language. However, functions can be written in any language that compiles to WebAssembly. This includes JavaScript, which is widely known and familiar to many developers. The ability to write functions in JavaScript eliminates the need to learn a new language, making it more accessible to a larger audience of developers.

What's New in 2023

Shopify has introduced several new features and updates for functions in 2023. These updates open up new areas for customization and functionality. In the developer preview, merchants now have access to four new areas:

  1. Order Routing Location Rule API: This API allows developers to build custom logic to determine from which location an item should be fulfilled. This feature is useful for merchants with multiple fulfillment centers or warehouses.

  2. Cart and Checkout Validation API: With this API, developers can implement custom validation checks during the checkout process. This could include age verification, limiting product quantities per customer, or implementing additional security measures.

  3. Cart Transform API: The Cart Transform API enables developers to create bundles and apply custom logic to the individual products within a bundle. This makes it easier to manage inventory, calculate taxes and shipping weights, and ensure smooth fulfillment.

  4. Payment and Delivery Customizations API: This API empowers developers to customize and configure payment and shipping methods based on specific conditions. For example, certain payment methods or shipping options could be hidden or reordered based on the customer's location or cart contents.

These new APIs provide merchants with even more flexibility and control over the checkout process, allowing for greater customization and personalization.

Getting Started with Writing Functions

Now that we have covered the basics and explored the new features, let's dive into the process of getting started with writing functions. The Shopify documentation provides various examples and use cases for functions. Whether you are a beginner or an experienced developer, these resources will help you understand the fundamentals and provide insights into how functions can be implemented in your store.

To begin, you need to create a development store within your Shopify partner dashboard. This will serve as a sandbox environment for testing and building your functions. Once the store is set up, you can start a new project on your local machine using the Shopify CLI. This command-line tool simplifies the development process by providing templates and commands for creating and deploying functions.

After setting up your local environment, you can choose the programming language you want to use for your functions. Shopify functions can be written in JavaScript, which is a popular and widely supported language. This is great news for developers who are already familiar with JavaScript or have experience building apps with Node.js.

The Shopify CLI provides a template for creating a new Shopify app using JavaScript as the tech stack. This app will serve as the foundation for your custom functions. By leveraging the power of JavaScript, you can write functions that integrate seamlessly with your existing codebase and take advantage of the extensive JavaScript ecosystem.

Next, you need to define the input for your function by creating a GraphQL query in the input.graphql file. This query will specify what data your function requires, such as the card values, buyer identity, and total amount. By retrieving this information, you can perform various checks and validations within your function.

Once you have defined the input, you can proceed to implement the actual logic of your function in the index.js file. This is where you will write the code to validate the card, apply discounts, rearrange payment methods, or implement any custom business rules. The possibilities are endless, and the freedom to customize Shopify's backend logic gives you unparalleled flexibility.

After writing the function code, you can deploy it to Shopify using npm run deploy. This deploys your function and pushes the compiled module to Shopify, making it available for installation in your store. With just a few simple commands, you can bring your custom functions to life and unleash their full potential.

Use Cases for Shopify Functions

Shopify functions open up a world of possibilities for customizing and extending your store's functionality. Here are a few use cases where functions can be leveraged to enhance the shopping experience for your customers:

  1. Automatic Discounts: Build a function that applies automatic discounts during the checkout process based on specific conditions. For example, you could offer a volume discount when a customer purchases multiple quantities of the same item.

  2. Dynamic Payment Methods: Customize the available payment methods based on the customer's location, selected products, or other specific conditions. This gives you the flexibility to display and prioritize the most relevant payment options for each customer.

  3. Shipping Method Selection: Show or hide specific shipping methods based on the customer's cart contents, shipping address, or other specified criteria. This allows you to offer tailored shipping options and streamline the checkout process.

  4. Product Bundles: Create functions that enable the creation of product bundles, where customers can purchase multiple related items together at a discounted price. This encourages upselling and increases average order value.

  5. Checkout Validation: Implement custom validation checks during the checkout process. For instance, you can verify the age of the customer for age-restricted products or limit the quantity of certain products per customer.

These are just a few examples of how Shopify functions can be utilized to enhance your store's functionality and provide a more personalized shopping experience for your customers. The ability to customize and extend Shopify's backend logic gives you the flexibility to implement unique features and tailor the checkout process to your specific business requirements.

Performance Benefits of Functions

One of the key advantages of using functions is their improved performance compared to scripts. Functions execute significantly faster than scripts, allowing for quicker processing of backend logic. This is particularly beneficial during peak traffic periods or flash sales when the volume of transactions is high.

With functions, your store can handle sudden traffic spikes and large order volumes with ease. The faster execution times ensure a smooth and responsive shopping experience for your customers, minimizing any potential delays or interruptions. This not only enhances the user experience but also boosts customer satisfaction and encourages repeat purchases.

By leveraging the performance benefits of functions, you can deliver a seamless shopping experience to your customers, regardless of the traffic volume or order complexity.

Language Support for Functions

Shopify functions offer greater flexibility in terms of language support compared to scripts. While scripts could only be written in Ruby, functions support any language that compiles to WebAssembly. This includes popular languages like JavaScript, Rust, and more.

JavaScript support is particularly noteworthy as it is a widely adopted language with a large developer community. If you are already familiar with JavaScript or have experience building Node.js applications, you can leverage that knowledge to write functions for your Shopify store. This eliminates the need to learn a new programming language specifically for Shopify development, saving you time and effort.

The ability to use JavaScript for functions opens up opportunities for a broader range of developers to leverage and contribute to the Shopify ecosystem. Whether you have experience with frontend development, backend development, or full-stack development, JavaScript's versatility ensures that you can seamlessly integrate functions into your existing workflows.

Integration with the Shopify Admin Dashboard

A significant advantage of using functions is their seamless integration into the Shopify admin dashboard. Functions are accessible via the admin dashboard, allowing you to manage and configure them without the need to touch the code. This makes it easier to make changes or updates to your store's logic without requiring extensive technical knowledge.

For example, if you have a function that applies discounts during checkout, you can easily manage and configure those discounts directly within the Discounts section of the admin dashboard. This provides a user-friendly interface for non-technical users to control and customize the behavior of functions without relying on developers.

The integration of functions into the admin dashboard promotes collaboration and empowers merchants to take control of their store's functionality. It eliminates the dependency on external apps or custom development work for making changes, thus streamlining the process and enabling swift iterations.

Migration from Shopify Scripts to Functions

If you are currently using Shopify scripts, it is essential to plan for the transition to functions. Shopify has announced that Shopify scripts will be deprecated and no longer supported after August 13th, 2024. Therefore, it is crucial to migrate your scripts to functions to ensure ongoing functionality and compatibility.

Migrating from scripts to functions offers multiple benefits, including improved performance, language flexibility, and increased accessibility. It also opens up new opportunities for distributing your custom features and functionalities through the Shopify App Store.

If you have been building and validating scripts for Shopify Plus clients, the migration presents an excellent opportunity to transition your services into white-labeled functions and offer them as a service or as a product on the App Store. This allows you to leverage the growing demand for functions and reach a wider audience.

By planning and executing the migration from scripts to functions, you can future-proof your Shopify store, ensure ongoing compatibility, and take advantage of the latest features and enhancements offered by functions.


In conclusion, Shopify functions provide an unparalleled level of customization and extensibility for your Shopify store. With functions, you can unleash the full potential of your store by customizing the backend logic, implementing unique features, and enhancing the customer experience. The ability to write functions in JavaScript, improved performance, and seamless integration with the Shopify admin dashboard make functions accessible and user-friendly for developers and non-technical users alike.

Whether you want to apply automatic discounts, personalize payment methods, validate the checkout process, or create product bundles, functions offer a powerful toolset to accomplish these goals. By migrating from Shopify scripts to functions, you can ensure ongoing support and compatibility while leveraging the latest features and enhancements.

So, why wait? Explore the possibilities of Shopify functions, experiment with JavaScript, and create a truly unique and tailored shopping experience for your customers.

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