I'm Hernani, a Java backend developer — Spring Boot, REST APIs, PostgreSQL. Recent Software Engineering graduate looking for my first backend role, with a background in low-level systems programming (Rust) that shapes how I think about state and correctness.
Munehisa — a risk-free investment simulator: trade real historical market prices month by month to see how a strategy would actually have played out.
- 25-endpoint REST API, Java 21 / Spring Boot 4.1, layered controller → service → repository
- JWT-based stateless auth (Spring Security), email verification, password reset
- PostgreSQL 16 + Flyway; 51 test classes (JUnit 5, Mockito, Testcontainers) in a 3-stage CI pipeline, plus k6 load testing
- 12 ADRs and 15 Business Rule Records documenting every architectural and domain decision
- Deployed live: React/TypeScript frontend on GitHub Pages, API on a Hetzner Cloud VM
Backend: Java · Spring Boot · Spring Security · Spring Data JPA · PostgreSQL · Flyway Testing: JUnit 5 · Mockito · Testcontainers · k6 DevOps: Docker · GitHub Actions · Maven Also: Python/FastAPI · React/TypeScript · Rust
Before backend, I spent time building interpreters and emulators — including a RISC-V RV32IMA emulator that boots a real no-MMU Linux kernel, compiled to WebAssembly and running live on my portfolio. It's where the habit of modeling state explicitly and making invalid states unrepresentable comes from, and it still shows up in how I design service-layer business rules today.
- Portfolio: https://hernanisamuel.github.io/meu_portfolio/
- LinkedIn: https://www.linkedin.com/in/hernanisamueldiniz/
- Email: hernanisamuel0@gmail.com
- GitHub: https://github.com/HernaniSamuel