AWS Essentials

Production-ready patterns for AWS core services: Lambda handlers, S3 operations, RDS connection management, IAM policies, async messaging, DynamoDB design, CloudFront caching, and cost optimization.

Lambda Handler Patterns

BAD: Unoptimized cold starts, no reuse

// TypeScript - AWS SDK v3
import { DynamoDBClient, PutItemCommand } from '@aws-sdk/client-dynamodb';

export const handler = async (event: any) => {
  const client = new DynamoDBClient({ region: 'us-east-1' }); // ❌ Created every invocation
  const apiKey = 'hardcoded-key-abc123'; // ❌ Hardcoded credentials