Azure App Service

What is App service API app?

API Apps are the Azure App Service that offers a rich platform and ecosystem for building, consuming, and distributing APIs
The API Apps enhance the experience of developing, deploying, publishing, consuming, managing and monetizing RESTful Web APIs
Existing APIs can take advantage of the API Apps platform with no changes
- it can connect to Azure Active Directory
- easy connection to SaaS platforms
- it can be consumed by Logic Apps
API App is specific for developing RESTful APIs with feature like Swagger out of the box

Both uses same compute service (Azure App Service)
All features available for one is available to the other
No differences under the hood. Only different icons, name and an API Definition that is populated

API apps are created using ‘Visual Studio > ASP.Net core web appplication > API’ template hosted in Azure App Service
API management is about managing APIs - the APIs being managed will be hosted anywhere i.e. in Azure or on-premise
Details: API Management vs API apps

Authentication and authorixation out of the bos
Single sign-on and OAuth
- Azure Active Directory
- OpenID connect - Google, Facebook, Twitter etc.
Develop or bring in existing APIs
Consume APIs on any website with CORS support
Integrate with API Management, Logic Apps, and many other Azure services
Use Swagger to generate cross-platform client SDKs in Visual Studio