Shopify Customization & Development

How to create a 100% custom theme for your Shopify store?

In 2026, the reference method for local Shopify theme development is no longer Theme Kit, but Shopify CLI. Here is the recommended workflow:

1. Initialize your theme project: use Shopify CLI to create the base of your theme or start from an existing Git repository.
2. Start a local development environment: launch a preview connected to your store to see your changes in real-time with actual store data.
3. Structure your theme correctly: templates, sections, snippets, assets, locales, and configuration files must follow the standard Shopify architecture.
4. Develop your theme: use Liquid, HTML, CSS, JavaScript, and JSON as per project needs.
5. Upload your changes to Shopify: push your modifications to a draft theme or an unpublished theme before going live.
6. Publish only after validation: once testing is complete, publish the validated theme to the store.

Tip: always combine Shopify CLI with Git to properly version your changes and avoid working directly on the live theme.

If you want to first develop a strategy to boost your Shopify store's conversion rate, read this article!

Can I add specific features to my store?

Yes, Shopify allows you to add specific features to your store in several ways, depending on the level of customization desired:

1. Shopify Apps: the Shopify App Store allows you to quickly add ready-to-use functionalities.
2. App blocks and app embeds: on compatible themes, this is currently the cleanest approach to integrate an application without manually modifying the theme code.
3. Custom front-end development: you can create your own behaviors and interfaces with Liquid, CSS, and JavaScript.
4. Advanced integrations via API and extensions: for more advanced needs, it is possible to develop applications, automations, extensions, or connections with external services.

This article on features in Shopify will allow you to learn more.

How to integrate custom scripts (JavaScript, CSS)?

In 2026, there are several ways to add custom code to Shopify, depending on your needs:

1. For simple CSS: primarily use the custom CSS field available at the theme or section level when sufficient.
2. For more advanced modifications: modify the theme code via the Shopify code editor and add your files to the correct locations (assets, sections, snippets, templates...).
3. For modern application integration: prioritize app blocks, app embeds, and theme app extensions, which avoid manual theme editing and limit the risk of breakage.
4. For older themes: some historical integrations still rely on code injection or remote scripts, but this logic should remain a legacy solution, not your first choice.

Avoid systematically adding all your scripts to the main layout: it's better to load only the necessary code, in the right place, to preserve performance.

How to use the Shopify API for advanced integrations?

The Shopify API allows for advanced integrations with external services, automations, and custom functionalities. In 2026, the recommended approach primarily relies on the Admin API GraphQL.

1. Choose the right application type: public application, custom distribution, or single-store dedicated application depending on your use case.
2. Configure necessary access: precisely define the permissions your application needs to read or modify store data.
3. Use the Admin API GraphQL: this is currently the reference API for new Shopify developments.
4. Reserve REST for legacy cases: some older integrations still use it, but it should no longer be your starting point for a new project.
5. Secure authentication: the authentication method depends on the application type and its distribution.
6. Add webhooks or extensions if necessary: they allow reacting to Shopify events and properly extending the platform.

We advise you to always consult the latest Shopify documentation before launching an advanced integration.

What programming languages are used in Shopify?

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

• Liquid: Shopify's own templating language for generating dynamic content on the theme side.
• HTML / CSS: for page structure and style.
• JavaScript: for interactions, dynamic behaviors, and front-end functionalities.
• JSON: for certain templates, settings, and theme configurations.
• GraphQL: for modern integrations with the Admin API.
• Node.js, TypeScript, Ruby, or other back-end stacks: on the application development side, the choice depends on the project and the architecture in place.

How to create and use custom applications in Shopify?

In 2026, the management of custom applications has evolved. New applications of this type are created and managed via the Dev Dashboard, and no longer according to the old operation of legacy custom apps.

1. Define your need: application dedicated to a single store, application distributed to multiple stores, or public application intended for the Shopify App Store.
2. Create the application in the right environment: use the Dev Dashboard for new custom apps and their management.
3. Configure API access: select only the necessary permissions.
4. Develop business logic: admin interface, automations, extensions, webhooks, data processing, etc.
5. Test in a suitable environment: use a development store or a test store before any actual deployment.
6. Install and maintain the application: monitor performance, logs, permissions, and developments of the Shopify platform.

How to 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 the store.
2. Preview your changes in real-time: use the development preview to check the display and behavior before going live.
3. Version your code with Git: this is essential for tracking changes, reverting if necessary, and collaborating cleanly.
4. If necessary, use Shopify GitHub integration: it allows you to synchronize a theme with a Git branch and better structure your workflows.
5. Analyze the code before deployment: tools like Theme Check can detect errors, risky practices, or performance issues.
6. Push then publish: first upload your changes to an unpublished theme, then publish only after full validation.

Does Shopify offer tools for developers?

Yes, Shopify provides several modern tools for developers:

• Shopify CLI: the primary tool for developing themes, applications, and other Shopify components.
• Theme Access: to provide secure access to a theme without sharing full store access.
• Shopify GitHub integration: to synchronize a theme with a GitHub repository.
• Theme Check: to analyze your theme code and identify errors, quality issues, and points of concern.
• Dev Dashboard and development stores: to build, test, and manage applications effectively.
• Official Shopify documentation: to follow platform evolutions, APIs, extensions, and best practices.

 

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