juniorAzure Service Bus
What is the difference between Queue and Topic in Azure Service Bus?
Updated Feb 20, 2026
Short answer
A queue sends a message to one receiver, while a topic sends messages to multiple receivers using subscriptions in Azure Service Bus.
Deep explanation
In a queue model, messages follow a point-to-point pattern. Each message is consumed by only one receiver. Once processed, it is removed from the queue.
In a topic model, messages follow a publish-subscribe pattern. A single message is published to a topic, and multiple subscriptions can receive their own copy of the message. Each subscriber processes the message independently.
This makes queues useful for load balancing work and topics useful for broadcasting events to multiple systems.
Real-world example
- Queue: A ticket booking system where each booking request is handled by one processing service.
- Topic: A new order event sent to inventory, billing, and shipping services at the same time.
Common mistakes
- - Thinking topics distribute messages randomly (they deliver copies to all subscriptions).
- - Using queues when multiple services need the same message.
- - Ignoring subscriptions in topic architecture.
Follow-up questions
- How do subscriptions filter messages?
- When should you choose queues over topics?
- Can a message go to both queue and topic?