In this advanced session on serverless workflow patterns, Ben Smith, Principal Developer Advocate for Serverless at AWS, shares insights from his experience building with AWS Step Functions. He covers why to use Step Functions first when building applications, different workflow modes, optimizing for cost reduction, and handling errors. Smith introduces patterns like REST APIs, nested workflows, and the new distributed map state for high-scale applications. He demonstrates how Step Functions can simplify serverless architectures, improve visibility into application flow, and reduce costs compared to Lambda-only implementations. Real-world examples like the serverlesspresso demo and a serverless GIF generator showcase Step Functions' capabilities for building robust, scalable workflows. The talk provides best practices and patterns for leveraging Step Functions' full potential in production serverless applications.