AWS Certified Solutions Architect Professional SAP-C02 Practice Question

Sending the order events to an Amazon EventBridge event bus cleanly decouples producers from consumers. Producers call the PutEvents API and have no knowledge of who is listening. EventBridge rules provide serverless, declarative content-based filtering, so each microservice receives only the events it cares about without custom code. Rules can be added at any time, enabling new microservices or SaaS partners to subscribe without changing the Order service. EventBridge is fully managed and pushes events to up to five targets per rule, including Lambda, SQS, SNS, and API destinations, eliminating the need to run or scale messaging infrastructure.

Publishing to an SNS topic (standard or FIFO) does provide fan-out, but filter policies are limited and do not support the advanced content-based filtering or cross-account SaaS integrations required. Writing to a single SQS queue forces consumers to poll and add in-code filtering, creating tight coupling and operational overhead. A synchronous Step Functions workflow still couples services together in a fixed sequence and requires state-machine updates whenever a new consumer is added, violating the loose-coupling requirement.