#api-gateway

Deploy and manage API gateways with rate limiting, authentication, and security controls for microservices architecture. API Gateway features: 1. Request routing: path-based routing, host headers, query parameters, weighted routing for A/B testing. 2. Protocol translation: REST to GraphQL, HTTP to gRPC, WebSocket support. 3. Response transformation: data format conversion, header modification, CORS handling. 4. Caching: response caching (5-minute TTL), cache invalidation, edge caching integration. Rate limiting strategies: 1. Throttling levels: per-API key (1000 req/min), per-IP (100 req/min), global limits. 2. Rate limiting algorithms: token bucket, sliding window, fixed window approaches. 3. Burst handling: temporary burst allowance, graceful degradation during spikes. Authentication methods: 1. API key management: key rotation, expiration policies, usage analytics. 2. OAuth 2.0/JWT: token validation, scope-based authorization, refresh token handling. 3. mTLS: certificate-based authentication, client certificate validation. Security controls: 1. Input validation: request size limits (10MB), content type validation, schema enforcement. 2. WAF integration: SQL injection prevention, XSS protection, bot detection. 3. DDoS protection: rate limiting, IP blocking, geographic restrictions. Monitoring and analytics: 1. Request metrics: latency percentiles (P50, P95, P99), error rates, throughput tracking. 2. API usage: top consumers, endpoint popularity, quota utilization. Load balancing: upstream health checks, circuit breaker pattern, retry mechanisms with exponential backoff.

Deploy and manage serverless applications using AWS Lambda with infrastructure automation and monitoring best practices. Lambda function optimization: 1. Runtime selection: Node.js 18+ for JavaScript, Python 3.9+ for data processing, Go for performance. 2. Memory allocation: 128MB-10GB, CPU scales proportionally, cost optimization through right-sizing. 3. Cold start mitigation: provisioned concurrency for critical functions, connection pooling. 4. Package optimization: tree-shaking for smaller bundles, layer usage for shared dependencies. Infrastructure management: 1. SAM (Serverless Application Model): template-driven deployment, local testing environment. 2. Serverless Framework: multi-cloud support, plugin ecosystem, environment management. 3. CDK (Cloud Development Kit): programmatic infrastructure, type safety, reusable constructs. Event-driven architecture: 1. API Gateway: REST/HTTP APIs, request/response transformation, caching (5-minute TTL). 2. Event sources: S3 triggers, DynamoDB streams, SQS/SNS integration, scheduled events. 3. State management: Step Functions for workflow orchestration, error handling, retry logic. Monitoring and observability: 1. CloudWatch metrics: invocation count, duration (target <1000ms), error rate (<0.1%). 2. X-Ray tracing: distributed tracing, performance bottleneck identification. 3. Log aggregation: structured logging, log retention policies, cost optimization. Security practices: IAM role-based access, VPC configuration for database access, secrets management with Parameter Store/Secrets Manager, input validation.