Azure Service Bus Queues

Azure Service Bus queues provide reliable, point-to-point message delivery between a sender and a receiver. They are the simplest messaging primitive in Service Bus and are ideal for decoupling services in distributed architectures. This lesson covers queue fundamentals, how messages flow through a queue, the receive modes, and practical considerations for building production systems.

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What Is a Service Bus Queue?

A Service Bus queue is a durable, brokered message store. Messages are sent to the queue by one or more producers and consumed by one or more competing consumers. The queue guarantees:

• Durability — messages are stored in the broker until a consumer acknowledges them
• FIFO ordering — messages are delivered in the order they were enqueued (first-in, first-out), though competing consumers can process them out of order unless sessions are used
• At-least-once delivery — every message is delivered to at least one consumer
• Load levelling — the queue absorbs traffic spikes so consumers can process at their own pace

Queue vs Storage Queue

Azure offers two queue services: