An order-processing system publishes an event whenever a payment succeeds. Three downstream services (inventory, shipping, and analytics) must react independently. Analytics sometimes has high latency, but order processing must not be blocked. What is the best AWS approach to decouple these consumers?

Have order processing call each service synchronously via HTTPS and retry on failures.

Synchronous calls couple the producer to each consumer’s availability and latency. If analytics is slow or temporarily unavailable, order processing can be delayed or fail, violating the requirement.

Store events in a single relational database table and let consumers poll continuously for new rows.

Polling a database couples scaling and failure handling to the DB layer and increases load. It also makes backpressure and failure isolation harder compared with managed messaging.

Send events directly from the producer to each consumer EC2 instance using SSH tunnels.

SSH-based delivery is not a resilient messaging pattern. It adds operational fragility (instance availability, networking, authentication/authorization, retries) and lacks the decoupling and durable delivery semantics expected for event distribution.

What does this SAA-C03 question test?

Read the scenario before looking for a memorised answer.

What is the correct answer to this question?

The correct answer is: Publish payment events to SNS (or EventBridge) and let each downstream service consume independently (for example, via SQS queues or other async targets). — To ensure slow consumers do not block order processing, use an asynchronous decoupling mechanism such as SNS or Amazon EventBridge. The order-processing system publishes a payment-success event once. Each downstream service consumes the event independently (commonly by subscribing via SQS, Lambda, or other async targets). This design provides failure and latency isolation: if analytics is slow or experiences transient issues, inventory and shipping can continue processing based on their own event consumption and scaling behavior. A is wrong because synchronous HTTPS ties order-processing responsiveness to the slowest consumer. C is wrong because database polling is a coupled approach that can create scaling and failure isolation problems at the database layer. D is wrong because SSH tunnel delivery is brittle and does not provide the managed pub/sub decoupling needed for resilience.

What should I do if I get this SAA-C03 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.