Theme Check

Theme Check is a linter for the Liquid and JSON inside your theme and theme app extensions. It detects errors and enforces Shopify theme and Liquid best practices.

Theme Check can identify several issues in your theme code. For example, it can identify the following:

Liquid syntax errors
Missing templates
Unused variables and snippets
Unknown and deprecated tags
Excessive snippet nesting
Performance issues

Programming and style errors display directly in your console or code editor. Each error includes a link to the failed check's documentation, allowing you to debug issues quickly.

You can use Theme Check in the following ways:

Through Shopify CLI - Run checks against your theme on demand.
As a Visual Studio Code plugin - Add Theme Check to Visual Studio Code to get real-time validation of your theme code, including errors and auto-completion.
As a plugin for another editor - Integrate Theme Check with any editor that implements an LSP client.

Installation

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Configuration

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You can configure check options to override defaults, or enable or disable specific checks, or point to your own custom checks. To learn more, refer to Theme Check configuration.

Creating your own checks

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You can write your own checks in Ruby and then reference them in your configuration. To learn about how the existing checks are written, explore the theme-check repo.

Using Theme Check in other editors

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Theme Check is implemented using the Language Server Protocol (LSP). This means that you can implement Theme Check as a language server in any editor that implements an LSP client. View some example implementations in the Theme Check repo.