Shopify Customization & Development

How do you build a fully custom Shopify theme?

In 2026, the standard way to develop a Shopify theme locally is no longer Theme Kit, but Shopify CLI. Here is the recommended workflow:

  1. Initialize your theme project: use Shopify CLI to create your theme foundation or start from an existing Git repository.
  2. Start a local development environment: launch a preview connected to your store so you can see your changes in real time using actual store data.
  3. Structure your theme properly: templates, sections, snippets, assets, locales, and configuration files should follow Shopify’s standard architecture.
  4. Build your theme: use Liquid, HTML, CSS, JavaScript, and JSON depending on your project’s needs.
  5. Push your changes to Shopify: send your updates to a draft or unpublished theme before pushing anything live.
  6. Publish only after validation: once testing is complete, publish the approved theme to your store.

Tip: always pair Shopify CLI with Git so you can version your changes properly and avoid working directly on your live theme.

If you would like to first develop a strategy to boost your Shopify store’s conversion rate, read this article.

Can I add custom features to my store?

Yes, Shopify allows you to add custom functionality to your store in several ways, depending on the level of customization you need:

  1. Shopify apps: the Shopify App Store lets you quickly add ready-made features.
  2. App blocks and app embeds: on compatible themes, this is now the cleanest way to integrate an app without manually editing theme code.
  3. Custom front-end development: you can build your own custom behaviors and interfaces with Liquid, CSS, and JavaScript.
  4. Advanced integrations through APIs and extensions: for more complex needs, you can build apps, automations, extensions, or integrations with external services.

This article on Shopify features will help you learn more.

How do I add custom scripts (JavaScript, CSS)?

In 2026, there are several ways to add custom code to Shopify, depending on what you need:

  1. For simple CSS: first use the custom CSS field available at the theme or section level whenever that is enough.
  2. For more advanced changes: edit your theme code through the Shopify code editor and add your files in the appropriate locations (assets, sections, snippets, templates, and so on).
  3. For modern app integrations: prioritize app blocks, app embeds, and theme app extensions, which avoid manual theme edits and reduce the risk of breaking the site.
  4. For older themes: some older integrations still rely on code injection or remote scripts, but this should be treated as a legacy approach, not your first choice.

Avoid adding all your scripts directly to the main layout by default. It is better to load only the code you actually need, in the right place, to preserve performance.

How can I use the Shopify API for advanced integrations?

The Shopify API makes it possible to build advanced integrations with external services, automations, and custom functionality. In 2026, the recommended approach is to prioritize the Admin API GraphQL.

  1. Choose the right type of app: public app, custom distribution, or an app dedicated to a single store depending on your use case.
  2. Set up the required access scopes: define exactly which permissions your app needs in order to read or modify store data.
  3. Use the Admin API GraphQL: this is now the reference API for new Shopify development.
  4. Keep REST for legacy use cases: some older integrations still rely on it, but it should no longer be your starting point for a new project.
  5. Secure authentication properly: the authentication method depends on the type of app and how it is distributed.
  6. Add webhooks or extensions when needed: they let you react to Shopify events and extend the platform in a clean way.

We always recommend relying on Shopify’s latest documentation before starting any advanced integration.

What programming languages are used in Shopify?

Shopify relies on several languages and technologies depending on whether you are building a theme or an app:

  • Liquid: Shopify’s templating language used to render dynamic content in themes.
  • HTML / CSS: used for page structure and styling.
  • JavaScript: used for interactions, dynamic behavior, and front-end functionality.
  • JSON: used for certain templates, settings, and theme configurations.
  • GraphQL: used for modern integrations with the Admin API.
  • Node.js, TypeScript, Ruby, or other back-end stacks: on the app development side, the best choice depends on the project and the overall architecture.

How do you create and use custom apps in Shopify?

In 2026, custom app management has evolved. New apps of this type are created and managed through the Dev Dashboard rather than through the old legacy custom app workflow.

  1. Define your needs: an app for a single store, an app distributed across multiple stores, or a public app intended for the Shopify App Store.
  2. Create the app in the right environment: use the Dev Dashboard for new custom apps and for ongoing management.
  3. Configure API access: select only the permissions your app actually needs.
  4. Build the business logic: admin interface, automations, extensions, webhooks, data processing, and more.
  5. Test in an appropriate environment: use a development or test store before any real deployment.
  6. Install and maintain the app: monitor performance, logs, permissions, and ongoing changes across the Shopify platform.

How do I test and deploy changes to my store?

To test and deploy changes to your Shopify store in 2026:

  1. Develop locally with Shopify CLI: work on your theme in a development environment connected to your store.
  2. Preview your changes in real time: use the development preview to check the display and behavior before publishing anything live.
  3. Version your code with Git: this is essential for tracking changes, rolling back when needed, and collaborating efficiently.
  4. Use Shopify’s GitHub integration when relevant: it helps sync a theme with a Git branch and creates a more structured workflow.
  5. Review your code before deployment: tools like Theme Check can identify errors, risky patterns, or performance issues.
  6. Push first, then publish: send your changes to an unpublished theme first, then publish only after full validation.

Does Shopify provide tools for developers?

Yes, Shopify provides several modern tools for developers:

  • Shopify CLI: the main command-line tool for building themes, apps, and other Shopify components.
  • Theme Access: used to grant secure access to a theme without sharing full store access.
  • Shopify GitHub integration: used to sync a theme with a GitHub repository.
  • Theme Check: used to analyze your theme code and identify errors, quality issues, and potential concerns.
  • Dev Dashboard and development stores: used to build, test, and manage apps in the right environment.
  • Official Shopify documentation: used to stay up to date on platform changes, APIs, extensions, and best practices.

 

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