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Getting Started with AWS Lambda

Welcome to AWS Lambda​

AWS Lambda is a serverless compute service that lets you run code without provisioning or managing servers. You upload a function, define what triggers it, and AWS handles everything else — scaling, availability, and the underlying infrastructure.

You pay only when your code runs, billed in 1-millisecond increments. Zero traffic means zero cost.

Why Lambda?​

Traditional servers run 24/7 even when idle. Lambda flips this model — your code only executes in response to an event, and AWS automatically scales from zero to thousands of concurrent executions.

Key benefits:

  • No server management — no OS updates, no capacity planning
  • Automatic scaling — scales instantly with incoming requests
  • Cost efficiency — pay per invocation, not per hour
  • Event-driven — integrates natively with the entire AWS ecosystem

Common Use Cases​

  • REST APIs — via API Gateway + Lambda (the serverless backend pattern)
  • File processing — trigger a function when a file is uploaded to S3
  • Scheduled jobs — run cleanup scripts or reports on a cron schedule
  • Database triggers — react to DynamoDB stream changes
  • Webhook handlers — respond to events from Stripe, GitHub, etc.

What You'll Learn​

  • Function anatomy — handler, event, context, and return value
  • Triggers — API Gateway, S3, SQS, EventBridge (CloudWatch Events)
  • Deployment — uploading code via the console, CLI, and frameworks like Serverless or SAM
  • Environment variables — managing secrets and config in Lambda
  • Layers — sharing common dependencies across multiple functions
  • Cold starts — understanding latency and how to minimize it

Prerequisites​

  • An AWS account with basic IAM knowledge
  • Familiarity with Node.js or Python (Lambda supports both)
  • Understanding of HTTP request/response cycle