How to Build Responsive APIs with Amazon API Gateway: A Guide to Response Streaming

Today, Amazon Web Services (AWS) unveiled a new feature for Amazon API Gateway – response streaming. This update is a game-changer for enhancing the responsiveness of your REST APIs by progressively streaming response payloads back to the client. This can significantly improve user experience, especially for AI-driven applications, web, and mobile apps, large file streaming, and long-running operations with incremental progress reporting.

Imagine you’re using an AI-powered application with complex interactions. Previously, users would ask questions and wait for responses, leading to a disconnected experience. But with response streaming, the API Gateway now allows your application to stream back responses in real-time, making the interaction seamless and engaging. This improvement transforms the user experience, reducing wait times and creating a more natural flow.

In the traditional request-response setup, the complete response had to be generated before being sent to the client, causing delays and impacting user experience. This was a particular issue for cloud applications like AI agents, chatbots, and other latency-sensitive functions. Additionally, handling larger response payloads, such as images or documents, posed challenges with response size limits and integration timeouts. Response streaming solves these issues by enabling streamed responses, enhancing performance, supporting larger payloads, and longer request processing times.

Response streaming has already proven to deliver significant performance gains for organizations. Drew Lau, Senior Director of Product Management at Salesforce Commerce Cloud, highlighted how enabling response streaming improved storefront experiences, exceeding performance goals and enhancing revenue opportunities for customers.

To get started with response streaming, update your API integration configuration to set the response transfer mode to STREAM. This allows API Gateway to begin streaming responses to clients as data becomes available. You can configure request timeouts for up to 15 minutes and are encouraged to implement response streaming in your backend for optimal performance.

Enabling response streaming can be done through the API Gateway console, Open API spec, or infrastructure-as-code frameworks like AWS CloudFormation. By choosing response streaming, you’re taking a significant step towards a more responsive and engaging user experience, without the hassle of managing infrastructure limitations.