In a video featuring Scott Guthrie, Executive Vice President of Microsoft Cloud + Enterprise on March 24, 2015, Microsoft announced a new application service available in Azure. The big news here is that the service allows developers to compose communication pipelines between applications and APIs. At a high level, Apps Service makes it easier to compose complex systems from existing web-based APIs and applications. The services consist of Web Apps, Mobile Apps, Logic Apps and API Apps.
Figure 1, Azure App Service
Although Figure 1 presents the components as peers, the correct way to look at them is that Web Apps, Mobile Apps, and Logic Apps all consume API Apps. Web Apps are built upon the existing Azure websites technology. Mobile Apps are built upon the existing Mobile services technology and Logic Apps are built upon the existing BizTalk services technology.
Composition uses JSON metadata known as “swagger” that drives a visual composition tool, which supports creating Logic Apps. Swagger metadata is exposed by many APIs already, which are available directly in the composition tool. You can also expose swagger metadata from your own custom APIs and participate in composition. Figure 2 shows the composition tool.
Figure 2, Composing Logic Apps
For SharePoint and Office developers, there is no earthshaking change to the way we create SharePoint apps or Office 365 applications. Instead, we get better support for scalability, management and composition.