So you want to build your first serverless function? Let's do it. No fluff, no detours — just you, AWS SAM, and a working Lambda function running on your machine in minutes. We're not even going to deploy to AWS yet. Let's just get it working locally first.

What You'll Need

Two things:

AWS SAM CLI installed — SAM (Serverless Application Model) is the tool we'll use to create, build, and test our function. Follow the install guide for your operating system.

Docker or Finch installed — SAM uses a container runtime to simulate Lambda locally. You have two options:

Docker Desktop — The most common option. Install it and make sure it's running.

Finch — A lightweight open source alternative from AWS.…