The Shopify Storefront API
The Storefront API is an unauthenticated GraphQL API.
It provides access to shop resources like products, collections, menus, carts, Checkouts and more. The Storefront API is what enables a headless Shopify storefront to be built.
In fact, the posibilities the Storefront API opens are endless. For example, it empowers developers to integrate shopping elements directly inside games or in unique places like vending machine screens.