Multi-AZ library management system on AWS with Route 53 DNS, CloudFront CDN, and WAF protection routing traffic through Application Load Balancers to microservices across two availability zones. EC2 instances handle borrow and return services, Lambda executes fine calculations, ECS Fargate runs the catalog service, and API Gateway orchestrates requests via Step Functions. RDS Aurora provides multi-AZ database replication for book, reader, and borrowing records, while ElastiCache Redis and DynamoDB Global Tables ensure low-latency session and metadata access with automatic failover. This architecture demonstrates AWS best practices for fault tolerance, auto-scaling, and operational visibility using CloudWatch, CloudTrail, IAM, and Secrets Manager. Fork and customize this diagram on Diagrams.so to adapt the topology for your library's scale, add additional microservices, or modify database schemas. Consider adding SQS for asynchronous notification queues and S3 for audit logs and backup retention policies.