Co-built MiraiAcademy, a full-stack EdTech platform on a self-managed OpenStack private cloud. I developed the backend (Spring Boot 3, Java 17, Modulith architecture) and contributed to the Angular 18 frontend, enabling real-time messaging via WebSockets, AI-assisted tutoring, and JWT multi-role auth. I also automated the infra: a 3-node K3s cluster provisioned via OpenStack Heat, configured with Ansible, deployed through GitHub Actions CI/CD, and monitored with Prometheus, Grafana and Alertmanager, with HPA autoscaling. Result: a production-grade platform with 93.7% simulated uptime.