I would design a scalable microservices architecture using independent services communicating through a private network, which improves security and reduces latency. Each service would have its own database to ensure loose coupling. For inter-service communication, I’d use an HTTP client such as Feign or asynchronous messaging when needed. To achieve scalability, I’d containerize each service with Docker and orchestrate them using Kubernetes, allowing horizontal scaling based on demand. Additionally, I’d implement an API Gateway for routing, centralized authentication, and load balancing. Monitoring tools like Prometheus and centralized logging would help maintain visibility across services.