AWS API Gateway — Complete Cloud-Native Gateway Guide

In this tutorial, you will learn about AWS API Gateway. We cover key concepts, practical examples, and best practices to help you master this topic.

AWS API Gateway is a fully managed service that makes it easy to create, publish, maintain, monitor, and secure APIs at any scale. It integrates natively with AWS Lambda for Serverless architectures.

What You'll Learn

You'll learn how to create REST and HTTP APIs, configure Lambda integrations, and set up API keys and usage plans.

Why It Matters

AWS API Gateway eliminates gateway infrastructure management. It scales automatically, integrates with AWS WAF, CloudWatch, and IAM, and supports both REST and Websocket APIs.

Real-World Use

A serverless startup runs 100 APIs on AWS API Gateway with Lambda backends. The gateway handles authentication via Cognito, throttling via usage plans, and monitoring via CloudWatch. Zero infrastructure management overhead.

Implementation

# AWS SAM template
AWSTemplateFormatVersion: '2010-09-09'
Resources:
  MyAPI:
    Type: AWS::Serverless::Api
    Properties:
      StageName: prod
      Auth:
        DefaultAuthorizer: AWS_IAM
        AddDefaultAuthorizerToCorsPreflight: false
      EndpointConfiguration: REGIONAL
      MethodSettings:
        - ResourcePath: "/*"
          HttpMethod: "*"
          ThrottlingRateLimit: 1000
          ThrottlingBurstLimit: 500
          CacheTtlInSeconds: 60
          DataTraceEnabled: true

  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: ./src
      Handler: app.handler
      Runtime: python3.11
      Events:
        GetUsers:
          Type: Api
          Properties:
            RestApiId: !Ref MyAPI
            Path: /api/users
            Method: GET

# Lambda handler for API Gateway
import json

def handler(event, context):
    http_method = event["httpMethod"]
    path = event["path"]
    user_id = event["pathParameters"]["userId"]

    if http_method == "GET":
        return {
            "statusCode": 200,
            "headers": {"Content-Type": "application/json"},
            "body": json.dumps({"userId": user_id, "name": "John"})
        }

    return {"statusCode": 405, "body": "Method not allowed"}

Common Mistakes

| Mistake | Fix | |---------|-----| | No usage plans | Open to abuse | Create usage plans with rate limits per API key | | Cold starts causing timeouts | Increase Lambda memory or use provisioned concurrency | | CORS not configured | Browser apps blocked | Enable CORS on the gateway | | Logging all data (cost) | CloudWatch costs can be high | Selective logging with sampling | | No API keys for public APIs | Anyone can call your API | Require API keys with usage plans |

What's Next

Learn about NGINX Ingress Controller for Kubernetes.