What is an Azure Service Bus?

Azure Service Bus is a fully managed enterprise message broker that enables reliable communication between decoupled applications and services, even when they aren't online at the same time.

Core Messaging Concepts

• Queues — point-to-point messaging where each message is consumed by a single receiver
• Topics and Subscriptions — publish-subscribe messaging where multiple receivers get a copy of each message
• Sessions — enable ordered, related message processing
• Dead-letter queues — hold messages that couldn't be delivered or processed successfully

Why Use Service Bus

• Decouples producers and consumers so services can scale independently
• Guarantees at-least-once (and optionally ordered) message delivery
• Supports transactions across multiple messaging operations
• Integrates with Azure Functions, Logic Apps, and most Azure compute services

Common Use Cases

• Order processing systems that need reliable, asynchronous workflows
• Load leveling between a fast producer and a slower consumer
• Broadcasting events to multiple downstream systems via topics