If you think API Gateway is simply "an HTTP proxy for Lambda", you only know half the story. API Gateway can call AWS services like DynamoDB, SQS, Kinesis, and S3 directly, without Lambda. The reason this pattern matters in practice is clear — skipping Lambda reduces latency, reduces cost, and leaves no code to manage.
Today we dissect API Gateway's five integration types and dig into how to transform requests and responses with VTL (Velocity Template Language) mapping templates. Once you understand the difference between Lambda Proxy and non-Proxy at the code level, real-world problems like "why doesn't CORS work?" and "why is my response format broken?" get solved instantly.