AWS API Gateway Primer
API Gateway sits between your clients and your backend services. It handles auth, rate limiting, request transformation, and routing so your Lambdas and EC2 instances stay focused on business logic.
REST vs HTTP vs WebSocket
REST APIs give you full control over stages, usage plans, and API keys. HTTP APIs are cheaper and faster for proxy workloads. WebSocket APIs handle persistent bidirectional connections for real-time features.
Lambda Authorizers
A Lambda authorizer runs before your route handler. It validates tokens, checks scopes, and returns an IAM policy. Cache the result to avoid invoking it on every request.
Mapping Templates
VTL templates transform incoming requests before they hit your integration. Use them to reshape JSON payloads, inject headers, or reject malformed input at the edge.
Next step: Wire API Gateway to a Lambda backend