Multi-AZ QR-based student attendance system with SMS notifications leverages Route 53, CloudFront CDN, WAF, and Shield for secure global access. QR Scanner Terminals feed attendance data through API Gateway to EC2 app servers, which trigger Lambda QR Processor functions that write scan events to DynamoDB and SQS. Lambda SMS Dispatcher consumes the queue, publishes notifications via SNS to Parents/Guardians, while RDS Aurora and ElastiCache provide highly available data persistence across ap-southeast-1a and ap-southeast-1b. This architecture demonstrates enterprise-grade resilience, security, and scalability for real-time educational workflows. Fork this diagram on Diagrams.so to customize subnets, instance types, or add additional notification channels like email or push notifications.