Vu T.

I'm a backend developer with 10+ years of professional experience — including full-time roles before moving to freelance/contract work — building and maintaining production systems with Java (Spring Boot) and C# (.NET), from API development and database design to cloud deployment and production troubleshooting. 🧩 What I Do • Build backend services and REST APIs using Java (Spring Boot) and C# (.NET) • Design and work with relational and NoSQL databases: PostgreSQL, MySQL, MongoDB • Build and deploy cloud infrastructure on GCP using Terraform and Kubernetes • Set up CI/CD pipelines and containerized deployments with Docker • Refactor and improve existing codebases without unnecessary rewrites • Troubleshoot production issues, performance problems, and complex business logic • Write automated tests and improve code quality and maintainability • Use AI coding tools such as Claude Code and OpenAI Codex to accelerate development, refactoring, debugging, testing, and codebase analysis — while keeping engineering decisions and code quality under control • Basic front-end skills (HTML/CSS/JS) when a feature needs some work beyond the backend ⚡ How I Work I prefer to understand the problem and the existing system first, then make the smallest practical change that solves the problem without unnecessarily rewriting working code. I'm comfortable working with existing enterprise systems, complex business logic, integrations, legacy codebases, and production issues — not only building new services from scratch. 🏢 Domain Experience • Billing systems — contracts, customers, resellers, monthly and yearly/final invoicing • Energy & IoT data systems — backend services, analytics, and data pipelines • Enterprise platforms — production software for finance and business operations 💬 Why Work With Me • 10+ years of software development experience • 100% Job Success on Upwork • Strong Java / Spring Boot and C# / .NET background • Hands-on cloud and DevOps experience with GCP, Terraform, Kubernetes, and Docker • Modern AI-assisted development workflow with Claude Code and Codex • Comfortable taking ownership from code → database → cloud → deployment • Clear communication and reliable delivery If you need a backend engineer who can work across code, database, cloud infrastructure, and modern AI-assisted development, let's talk about your project.