Azure Functions are the simplest and easiest way to develop, host, and manage microservices. They can be developed and hosted locally as well.

Azure Functions support development in various languages including C# and NodeJS, and you can write the code while staying within the Azure portal on your browser.

Azure Functions are basically meant to be event based, which means that they execute only when the desired event occurs; they get charged for up to milliseconds of the executable time, so you pay only when your function is executed, and not for any idle time. They scale automatically based on the load, and you do not need to configure the scaling limits or scaling factors at all. You do not need to manage any hosting environment either, thus reducing the DevOps to almost none.

Since Azure Functions are event based and promote the reactive microservices architecture, they provide an excellent number of input and output bindings for integration with various other systems to get events from. These bindings include Azure BLOB storage, table, Event Hub, queue storage, Azure service bus, HTTP, Azure notification hub, Twilio (SMS service), and more.

One Azure Function App is composed of one or more individual functions. All of the functions in a single function app share the same pricing plan, continuous deployment, and runtime version. You can write the functions in multiple programming languages, and they can all share the same function app.

With Azure Functions, you can develop and ship faster, with shortest development-to-deployment cycles, focusing only on the business logic, ideal for quick testing multiple versions with least worries about the cost, deployment, and maintenance.