TerraLog's three-tier web application architecture combines a ReactJS frontend with Spring Boot microservices and MySQL replication for high availability. User traffic flows through WAF and CDN to a ReactJS frontend, then routes via ALB to REST Controllers that invoke Business Services and JPA Repositories. The Data Layer uses MySQL Primary (db.r5.large) with synchronous replication to a MySQL Replica, ensuring read scalability and failover resilience. This pattern demonstrates separation of concerns across Presentation, Application, and Data layers while leveraging AWS managed services for security and performance. Fork this diagram on Diagrams.so to customize database instance types, add caching layers, or extend with monitoring and logging components.