How does the data exchange between the mobile application and the back office work?

Question

Mobile development

There is a task - to develop a mobile application for popular axes: android, ios windows phone.
The main task is to keep a calendar. Each user can register and log in, and his calendar is stored on the server.
Break the global web can not figure out how to implement the connection between the mobile application and the server? What can act as a back office and how to get an API for working on an exchange?

Answer 1

There is a wealth of information on this topic. The backend ( backoffice is still an incorrect term in this context) can be any REST service. The methods of this service are the API.
All the same, it is worth formulating the requirements for the application a little more precisely: should it be cross-platform? what platform to build the backend on?
Here is a video course showing the process of developing such an application in Xamarin with a ServiceStack backend.