SAA
Understanding Decoupled Design with SQS, SNS, and EventBridge
Learn the decoupled design patterns essential for SAA, and how to choose between SQS, SNS, and EventBridge based on their roles.
The SAA exam often tests your understanding of decoupled system design. The three main services for this are SQS, SNS, and EventBridge.
Summary
SQS is a queue, SNS is Pub/Sub notifications, and EventBridge is event routing. By avoiding direct connections between systems, you build architectures that are more resilient to failures and easier to scale.
What Is Decoupling?
Decoupling is a design approach that reduces the dependencies between components. When Service A calls Service B directly, slowness in B easily affects A.
Placing a queue or event bus between them lets you process work asynchronously, so a failure on one side is less likely to bring down the whole system.
The Role of SQS
SQS is a message queue. It temporarily stores messages waiting to be processed, and downstream workers pick them up in order.
Use it whenever you want asynchronous processing, such as image conversion, order processing, or batch jobs.
The Role of SNS
SNS is a Pub/Sub notification service. A single message can be delivered to many subscribers.
Use it when you want to fan out the same event in several directions, such as sending email notifications, invoking Lambda functions, or pushing to SQS.
The Role of EventBridge
EventBridge is an event bus. It routes events from AWS services, SaaS providers, and custom applications based on rules you define.
It also supports scheduled execution, so a feature like "deliver one question per day" is a good fit for EventBridge + Lambda.
Key Points for the SAA Exam
- SQS is an asynchronous queue
- SNS sends notifications to multiple subscribers
- EventBridge handles event routing and scheduled execution
- Decoupling improves fault tolerance and scalability
- Consider replacing synchronous calls with asynchronous patterns
Related Terms
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What to learn next
Combine blog posts with the AWS glossary, service comparisons, practice questions, and architecture gallery to connect exam knowledge with implementation.