Theme App Extension (App Block)

A mechanism for apps to inject functionality into Shopify themes as "blocks," without touching the theme's code. Available in OS 2.0 themes.

App functionality survives theme updates, and merchants can place blocks by drag and drop. It is the key design pattern for keeping apps decoupled from client themes.

We implement reusable, multi-store functionality — such as employee discounts and my-page enhancements — as App Blocks.