Modern enterprise platforms, particularly in the healthcare, banking, and government sectors, require highly resilient, low-latency, and secure backend systems that can scale. I have over 15 years of experience modernizing mission-critical systems, including Medicaid MMIS platforms, banking integrations, and federal identity systems, enabling a practical overview of designing and optimizing Java/Spring Boot microservices for production. The conversation covers the fundamentals of architecture, including distributed caching through Redis and AWS ElastiCache, database optimizations, asynchronous processing, and event-driven designs. The session consists of lessons on how to implement resilience patterns such as circuit breakers, bulkheads, retries, and fallback strategies in Spring Cloud and Resilience4j to achieve uptime and stable performance under heavy loads. We also discuss important production issues, such as API Gateway design, rate limiting, throttling, mTLS/JWT authentication, observability, and service communications in a secure manner, aligning each with real examples from Medicaid claims systems, healthcare provider enrollment platforms, banking workflows, and the modernization of government programs. This course is for developers, architects, and engineering leaders who want to make microservices fast, fault tolerant, capable of scaling, secure, and have techniques that can be applied in enterprises.