Azure Functions is a nifty little tool that allows you to run basic functions for extremely low costs, with the ability to scale up and down easily.  If your request stays under 100ms and 128mb of memory, it hits the ‘lowest’ cost of $0.0000002 each request, or roughly 5 million requests per $1.

If you are hosting your site and database on Azure, and your web application is taking a hammering because of a handful of APIs, you are faced with either scaling up/out your entire web app ($$$) or you could offload those APIs to Azure Functions instead.