---
title: Theme Check
description: Check your theme's Liquid and JSON to identify errors and apply best practices.
source_url:
  html: https://shopify.dev/docs/storefronts/themes/tools/theme-check/index
  md: https://shopify.dev/docs/storefronts/themes/tools/theme-check/index.md
---

# Theme Check

Theme Check is a linter for the Liquid and JSON inside your theme and [theme app extensions](https://shopify.dev/docs/apps/build/online-store/theme-app-extensions). It detects errors and enforces Liquid best practices.

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

* Syntax errors

* Missing templates

* Unused variables and snippets

* Unknown and deprecated tags

* 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, in CI or with our Language Server.

* **Via the Shopify Liquid Visual Studio Code extension** - Theme Check is included in the extension.

***

## Installation

* [Install Theme Check with Shopify CLI](https://shopify.dev/docs/api/shopify-cli)
* [Install the Shopify Liquid Visual Studio Code extension](https://shopify.dev/docs/storefronts/themes/tools/cli/language-server)

***

## Configuration

You can configure check options to override defaults, or enable or disable specific checks, or point to your own [custom checks](#creating-your-own-checks). To learn more, refer to [Theme Check configuration](https://shopify.dev/docs/storefronts/themes/tools/theme-check/configuration).

***

## Creating your own checks

You can write your own checks in TypeScript and then reference them in your [configuration](https://shopify.dev/docs/storefronts/themes/tools/theme-check/configuration). To learn about how the existing checks are written, explore the [`theme-tools` repo](https://github.com/Shopify/theme-tools/blob/main/docs/theme-check-common/writing-your-own-check).

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## Using Theme Check in other editors

Theme Check is available for integration in other editors using Shopify's [Language Server](https://shopify.dev/docs/storefronts/themes/tools/cli/language-server).

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## Command reference

[Checks reference\
\
](https://shopify.dev/docs/storefronts/themes/tools/theme-check/checks)

[Learn what each check does, how to configure it, and when to disable it.](https://shopify.dev/docs/storefronts/themes/tools/theme-check/checks)

[Command reference\
\
](https://shopify.dev/docs/storefronts/themes/tools/theme-check/commands)

[Review the Theme Check reference for commands.](https://shopify.dev/docs/storefronts/themes/tools/theme-check/commands)

***

## Contributing to Theme Check

Theme Check is open source and part of our suite of theme developer tools.

* Learn how to contribute to the [theme-tools repository](https://github.com/Shopify/theme-tools/blob/main/docs/contributing.md)

***