Which service is a serverless orchestration service that lets you integrate with AWS Lambda functions and other AWS services to build business-critical applications?

• A. Amazon AppFlow
• B. AWS Step Functions
• C. Amazon MQ
• D. Amazon OpenSearch Service

Answer: (B)

This question tests understanding of serverless workflow orchestration in AWS. The service that coordinates a sequence of tasks across Lambda and other AWS services using state machines is AWS Step Functions. It’s serverless, so there’s no infrastructure to manage, and it scales automatically. You define a workflow as a state machine where each state runs a task (such as a Lambda function, a Glue job, or a SageMaker job) and then moves to the next state, runs tasks in parallel, or waits for signals. Step Functions provides built-in error handling, retries, catch blocks, and timeouts, which helps keep business-critical processes—like order processing, data pipelines, approvals, and ETL—reliable. It integrates with Lambda and many other AWS services (DynamoDB, SQS/SNS, ECS, etc.), making it ideal for orchestrating complex workflows. The other services aren’t designed for this kind of orchestration: AppFlow focuses on data flows between SaaS applications, MQ is a messaging broker, and OpenSearch is a search/analytics service.