AWS S3, CloudFront, and Lambda — how do they work together for serverless?

Stack

S3 (static files) → CloudFront (CDN) → Users, Lambda (API) → API Gateway → CloudFront

// Lambda handler
export const handler = async (event) => {
  const apps = await prisma.application.findMany();
  return { statusCode: 200, body: JSON.stringify(apps) };
};
// Pay per invocation (~$0.20/1M requests), cold start ~200ms

ComponentTraditionalServerless

Compute$30/mo (always on)$5/mo (pay per use)
CDN + Storage$10/mo$6/mo
Total~$40/mo~$11/mo

Best for variable traffic. Not for constant heavy traffic or long-running processes.