Which service provides message delivery from publishers to subscribers (also known as producers and consumers)?

• A. Amazon Simple Notification Service (SNS)
• B. Amazon Simple Queue Service (SQS)
• C. Amazon EventBridge
• D. Amazon MQ

Answer: (B)

Pub/sub messaging lets a publisher send a message to a topic and have that message delivered to all subscribed endpoints. In AWS, the service that implements this pattern is Amazon Simple Notification Service (SNS). A publisher sends a message to an SNS topic, and multiple subscribers—such as HTTP/S endpoints, email, mobile push, or even SQS queues—receive that message, enabling decoupled, fan-out delivery to many recipients.

SQS is a queue that decouples producers and consumers in a point-to-point fashion; it delivers messages to a single consumer (or allows competing consumers to pull from the queue) rather than broadcasting to many subscribers. EventBridge focuses on routing events based on rules between services and apps, not classic pub/sub messaging to multiple endpoints. MQ is a managed broker for traditional messaging patterns using topics and queues, but it’s more aligned with brokered messaging than the cloud-native pub/sub model. So, the service designed for publishers delivering to multiple subscribers is SNS.