REST API is a set of rules or protocols that define how two systems can communicate with each other over the internet. In the context of Shopify, it refers to the APIs that allow apps to communicate with Shopify’s platform. Using the REST API, apps can Retrieve, create, update, and delete Shopify resources such as products, customers, and orders.
The REST API is based on the principles of Representational State Transfer (REST). This means that the API is designed to be easy to use and easy to understand. The API is built on top of the HTTP protocol, and uses HTTP methods (such as GET, POST, PUT, and DELETE) to specify the operation to be performed.
The REST API is the recommended way to interact with Shopify, and is much more powerful than the older Shopify API (aka the Order API). The REST API provides greater flexibility and allow apps to more seamlessly integrate with Shopify.
If you’re just getting started with developing Shopify apps, then we recommend checking out our documentation on the REST API:
https://docs.shopify.com/api/reference#intro