Rapid Mobile App Development (RMAD) with Microsoft PowerApps

PowerApps-related technologies

PowerApps
 PowerApps is an enterprise service for LoB and IT analysts and developers to connect, create, and share business apps across an organization on any device in minutes.
 The PowerApps tool allows you to create mobile apps that can run on iOS, Android, and Windows.

Swagger
 To consume HTTP services from PowerApps (like services in Azure App Service), those services need to expose Swagger metadata so that PowerApps can discover what can be consumed.
 Swagger is a very popular RESTful API description metadata so services can be discoverable from the outside. It is basically what Azure API Apps, Azure Logic Apps, and PowerApps use to understand how to use services/APIs and to connect to them.
 Azure API Apps already provide Swagger metadata by default, but if you want to consume Azure Mobile App services (or any other HTTP service, like a regular ASP.NET Web API service) from PowerApps, you need to add functionality so they provide Swagger metadata.

Swashbuckle
 Swashbuckle is a convenient way to rapidly and automatically generate Swagger metadata from a Web API .NET project, like any ASP.NET Web API service or an Azure Mobile App service.
 Swashbuckle is basically a NuGet component that you can add to your Web API service so that it automatically generates the Swagger metadata related to your methods (no need to manually generate it).

Source Of Information : Microsoft Platform and Tools for Mobile App Development