Magento2 has three different modes but official documents don't talk about how does Magento 2.2.6 REST APIs' behaves in these three different modes?
1 Answer
Yeah, you are right. Magento doesn't include how the Magento REST APIs behave on the different modes or its behavior on each mode because Magento REST APIs are intended supposedly for integration or integrating your Magento application with external or third party applications or systems which means it doesn't really affect or be affected by the internal modes of the Magento.
Let's say you want to develop a mobile app of your Magento webshop, the Magento REST APIs provide you with the ability to manage your webshop, allowing requests for working with resources such as customers, categories, products, and sales orders, and even carts and inventories by providing or exposing REST API endpoints depending on the type of the user making the requests as discussed in the Magento REST API documentation.