Introduction

If you have ever deployed an application the traditional way - provision an EC2 instance, install a runtime, keep it patched, watch it sit idle most of the day - AWS Lambda feels almost unfair. Lambda is AWS's serverless compute service: you upload your code, and AWS runs it for you in response to events. No servers to provision, no operating system to patch, and no paying for idle time. You are charged per request and for the exact duration your code runs, down to the millisecond.

This post is for Java and Spring Boot developers. We go through the basic concepts of Lambda - handlers, events, triggers, and limits - and then do two quick hands-on implementations with Spring Boot and Spring Cloud Function: a function you build locally with Maven, deploy through the AWS console and test, and the same idea exposed as an HTTP endpoint you can call with curl.…