Azure Queue enables messaging between different parts of applications. This is used in the development of highly scalable and flexible applications. Components of applications are often decoupled, to enable independent scalability for the individual parts. Queues are also used as an asynchronous method of communication between components that run on different locations (cloud, on-premises, desktop, mobile). It's also possible to build workflows and asynchronous tasks based on Azure Queues storage . One storage account has no limit on the number of queues, as well as the number of messages these contain. A single message can be up to 64 KB in size.

There are two different kinds of queues in Microsoft Azure:

• Azure Queues: This is a part of Azure Storage and the one that we are working with in this chapter
• Service Bus queues: This is a feature of Microsoft's Azure messaging infrastructure and has more advanced features for application development

According to Microsoft, Azure Storage queues should be used when your application must store over 80 GB of messages in a queue, where the messages have a lifetime shorter than 7 days. And, Service Bus queues should be used when you need more advanced features such as guaranteed First-In, First-Out (FIFO) ordered delivery, bigger handles, message receiving without polling, and so on.