Java 21, Spring Boot 3.x, REST APIs, Kafka, Event Sourcing/CQRS — production microservices
PostgreSQL optimization, high-load systems, real-time IoT/GPS data processing
AWS (EC2, RDS, S3) & VPS deployments — Docker, CI/CD, nginx, SSL
Spring Security (JWT, RBAC), Resilience4j, 93%+ test coverage with Testcontainers