Multi-AZ 3-tier B2B web service deployed across AWS Seoul region (ap-northeast-2) with load-balanced Apache web tier, Java/Spring application tier, and PostgreSQL database tier for high availability. Traffic flows from B2B users through an Application Load Balancer to Apache EC2 instances (t3.small) in public subnets across two availability zones, which route requests to Java/Spring application servers (t3.medium) in private subnets. Application tier connects to RDS PostgreSQL Primary (db.t3.medium) in AZ-1 with synchronous replication to a Standby instance in AZ-2 for automatic failover. This architecture demonstrates AWS best practices for fault tolerance, security through subnet isolation, and regional compliance for Korea-based B2B operations. Fork and customize this diagram on Diagrams.so to adjust instance types, add caching layers, or implement auto-scaling policies. Consider adding NAT gateways for outbound traffic and security groups to enforce least-privilege access between tiers.