Multi-AZ microservices architecture for P2P payments using AWS WAF, Cognito, API Gateway, and Route 53 for secure ingress. Six core services—Auth, User, Wallet, Transaction, Notification, and Fraud Detection—run in private subnets across two availability zones with ALB load balancing, Step Functions orchestration, and SageMaker ML fraud detection. PostgreSQL primary-standby, Redis ElastiCache, MSK Kafka, and DynamoDB provide resilient data layers with KMS encryption, CloudTrail audit logging, and real-time monitoring via CloudWatch and X-Ray. Fork this diagram to customize VPC CIDR blocks, add additional AZs, or integrate with your payment processor and compliance framework.