2.1. Developing with AWS Lambda & Serverless Applications

💡 First Principle: Serverless means you write functions, not servers — AWS handles everything from provisioning to scaling to patching. You pay only when your code runs.

What if you could deploy an API backend in minutes, have it scale from zero to thousands of concurrent requests automatically, and pay nothing when nobody's using it? That's the serverless promise. But without understanding the execution model — cold starts, concurrency limits, memory-to-CPU ratios — developers build functions that time out, cost too much, or fail silently under load.

Think of Lambda like a restaurant kitchen that hires cooks on demand: when orders come in, cooks appear; when the rush ends, they leave. You never pay idle cooks. But if you don't understand the hiring process (cold starts), your first customers wait longer than expected.

Loading diagram...

This section covers Lambda, API Gateway, SAM, and DynamoDB — the core serverless stack tested heavily on the DVA-C02.