If you choose to use Azure as a backend for your mobile app, you can use Azure's mobile services. It offers most infrastructure for you, including processing, storage, and scaling options. You can pick a pricing tier, such as free, one of the basic, or one of the premium plans. An example from the Microsoft document that shows how scaling works in Azure is provided in the following picture. The picture is taken from the classic environment and it looks a bit different in the 'new' portal; however, the way it is presented here is clearer:

Most Azure services, including the previously mentioned one, come with autoscaling. The solution will automatically scale up or down depending on traffic or by following schedules. Think, for example, of a day and night schedule, a weekend versus weekdays schedule, or a schedule for a specific period when you are running...