FastAPI microservices architecture on AWS with four independent services—Auth, Workflow, Catalog, and Document—deployed across private subnets behind an Nginx API Gateway in the DMZ. Each service connects to shared PostgreSQL and Redis instances in the data layer, with event-driven workflows via RabbitMQ MSK and AWS Step Functions for orchestration. The design demonstrates domain-driven microservices with JWT authentication, sidecar caching patterns, and S3 integration for document storage. Fork this diagram on Diagrams.so to customize subnets, add additional services, or adjust database instance types for your workload. This architecture balances operational simplicity with security best practices including WAF protection, Secrets Manager integration, and comprehensive observability via CloudWatch and X-Ray.