We design for performance by selecting an AWS Region closest to our primary user base and data-residency needs, then design for reliability by spreading workloads across at least two (often three) Availability Zones within that Region. At the application layer, we place stateless services behind an Elastic Load Balancer with Auto Scaling groups spanning multiple AZs, so traffic automatically shifts if an AZ degrades. For data, we use Multi-AZ managed services (for example, Amazon RDS Multi-AZ, DynamoDB, and S3) to get built-in replication and automated failover, and we keep session state externalized (Redis/ElastiCache or DynamoDB) to avoid single-node dependency. For regional resilience, we add cross-Region backups and, for critical systems, a warm-standby or active-active pattern using Route 53 health checks and DNS failover. This balances low latency with strong fault isolation and predictable recovery paths.