AWS Lambda Cheat Sheet

AWS Lambda is Amazon Web Services' serverless compute service that runs your code in response to events without you provisioning or managing servers, billing only for the compute time consumed. It sits at the center of event-driven and microservices architectures on AWS, integrating tightly with dozens of services across the platform. The key mental model to internalize: Lambda executes code inside short-lived, isolated execution environments that are frozen between invocations and reused when possible — understanding this lifecycle (cold start, warm reuse, and shutdown) is what separates practitioners who fight Lambda from those who design for it.