What is Azure Service Bus? 

Message buses and queues are a powerful tool communicating between applications. They are used extensively in microservices to decouple applications and services from each other providing benefits like load-balancing, safe routing and control across service and application. Microsoft Azure Service Bus is a reliable cloud messaging as a service (MaaS) with message queues and publish-subscribe topics. 

Concepts and Terminologies

Message: Transfer of data between different applications and services is called a message. A message contains business data such as sales and purchase order or any inventory status in different forms like JSON, XML or plain text.

Decouple applications: Service Bus improves reliability and scalability of applications and services. No consumer or producer are required to be online at the same time.

Load Balancing: Allow multiple consumers to read from a queue at an equivalent time, each safely obtaining exclusive ownership to specific messages.

Queues: Sender sends messages to queue and receiver receives the message from queue Messages stay in the queue until the receiver is available to receive and process them.



Topics: On the other hand, topics are same as queues the only difference is that same queue can be used or accessed by multiple receivers. Topics are useful in publish/subscribe scenarios. 

When to use Azure Service Bus?

Azure Service bus is the “Swiss Army Knife” service of all other generic messaging services. It is a solid workflow and transaction handling and has robust facilities for handling many applications fault conditions.

Service Bus functions as a bridge between hybrid cloud solutions and systems that include branch office or work site systems. Systems that sit “behind the firewall”, are roaming across networks, or are occasionally offline can’t be reached directly via “push” messaging, but require messages to be sent to a verified pickup location from where the designated receiver can obtain them.

When the business application lies in the cloud and on-site datacenter, then Service Bus queues and topic subscriptions are the ideal choice. This model is especially fashionable SaaS providers in health care, tax and legal consulting, restaurant services, and retail.