API Apps allows you to host Web APIs on Azure App Services. We can expose existing Web APIs, or develop a new Web API project, either from Visual Studio, or from the Azure portal with a few clicks.

It provides the following features:

• APIs that can be hosted on Azure App Services should be developed either on .NET, Java, PHP, Node.js, or Python.
• API Apps provides authentication and authorization out-of-the-box, and provides different connectors to authenticate using Facebook, Google, Microsoft accounts, Azure AD, as so on.
• It has built-in Swagger to see API metadata and consume through web. Swagger is a powerful open source framework, which provides certain tools that help to design, build, document, and consume RESTful APIs.
• It provides the Client SDK so that the party consuming that API can easily generate the client code through Visual Studio or command prompt, and this is supported for clients developed on .NET, Java, Node.js, and JavaScript.
• It supports CORS (Cross Origin Resource Sharing), which allows calling Web APIs from cross domains.
• It can be used in integration with Logic Apps, and Logic Apps can use orchestration to delegate calls to our Web APIs.
• We can easily do monitoring, scaling, setting up of deployment slots, and many other things through the Azure API Management interface.