---
title: "Overview"

doc_type: static
doc_category: static
doc_version: v20270301
source_url:
  html: 'https://developer.shopline.com/docs/online-store-3-0-themes/integrate-apps-with-themes/theme-app-extension/overview'
  md: 'https://developer.shopline.com/docs/online-store-3-0-themes/integrate-apps-with-themes/theme-app-extension/overview.md'
---
# Overview
A theme app extension allows merchants to directly integrate a third-party app into a store theme without modifying the original theme code. 

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## Benefits of using theme app extensions{#IhpQj}
With theme app extensions, you can achieve the following benefits: 

+ **Visual editing**: You can easily add, edit, or remove app components within the theme editor after installing apps that support theme app extensions in the store. 
+ **Bulk deployment**: A single release of the theme app extension can apply to all themes using it, streamlining the deployment process. 
+ **Seamless theme updates**: Themes leveraging theme app extensions can automatically upgrade alongside SHOPLINE OS 3.0 version themes without modifying the theme code, minimizing the risk of disruptive changes.

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## Limitations{#Lni6w}
There are some limitations on using theme app extensions:

+ Theme app extensions cannot be used on checkout pages. This includes all pages initiated by the customer during checkout, such as pages showing shipping methods and order status. 
+ The following [content](https://developer.shopline.com/docs/sline/tag/content.md) Sline tags cannot be used:
    - `{{#content "header" /}}`
    - `{{#content "layout" /}}`
    - `{{#content "footer" /}}`
+ The [section](https://developer.shopline.com/docs/sline/object/section.md) Sline object cannot be used. 

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## Theme app extension resources{#CyUFk}
The theme app extension primarily includes the following resources: 

+ **Blocks:** App blocks composed of Sline syntax that can be directly injected into themes. The following block types are supported:
    - App Blocks
    - App Embed Blocks 
+ **Public:** CSS, JavaScript, and other static app content injected into themes.
+ **Components:** Reusable Sline code snippets that can be used across multiple blocks. 

For more details on theme app extension resources, refer to [Theme app extension structure](https://developer.shopline.com/docs/online-store-3-0-themes/integrate-apps-with-themes/theme-app-extension/structure.md?lang=en).

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## Next steps{#tBCpg}
+ [Get started building theme app extensions](https://developer.shopline.com/docs/online-store-3-0-themes/integrate-apps-with-themes/theme-app-extension/get-started.md?lang=en)
+ [Configure the theme app extension structure](https://developer.shopline.com/docs/online-store-3-0-themes/integrate-apps-with-themes/theme-app-extension/structure.md?lang=en)