Multi-AZ microservices architecture spanning three AWS availability zones with containerized services, managed databases, and comprehensive observability for 50,000 concurrent users. Traffic flows through CloudFront CDN and Route 53 to Application Load Balancers distributing requests across Auth, User, Feed, Media, and Notification ECS services deployed in private subnets. PostgreSQL primary-standby-replica topology, DynamoDB global tables, Upstash Redis replicas, and S3 media storage with Glacier backups ensure data durability and low-latency access across zones. CloudWatch, X-Ray, CloudTrail, GuardDuty, and Security Hub provide full-stack observability and security posture management. Fork this diagram to customize service counts, instance types, or add additional microservices while maintaining high availability and disaster recovery patterns.