Trinh Long Vu
React / TypeScript Frontend & Java / Spring Boot Developer
Full-Stack Freelance Developer specializing in React / TypeScript frontend engineering and Java / Spring Boot backend architecture.
Helping clients build production-ready web applications, SaaS admin dashboards, financial tracking tools (such as LongHub), responsive UIs, RESTful API integrations, and database performance enhancements.
Freelance Engineering Services
Specialized frontend, backend, and full-stack solutions tailored for clients and modern web applications.
React Frontend Development
Custom React.js & TypeScript single-page applications, SaaS user interfaces, and responsive admin dashboards with modern state management.
Java & Spring Boot Backend
Production-ready backend architecture using Java 21 & Spring Boot, offering high-throughput RESTful APIs, security, and database integration.
Full-Stack Development
End-to-end web application development connecting React frontends with Spring Boot backends, databases, and third-party API services.
Existing Product Improvements
Targeted support for existing applications: bug fixes, performance tuning, UI/UX enhancements, code refactoring, and API updates.
Featured Engineering Case Studies
Real systems highlighting architectural decisions, technical trade-offs, and measurable outcomes.
LongHub — Stock Tracking & Portfolio Application
Full-stack financial market dashboard with portfolio management, paper trading, and real-time data feeds • Live Demo: longhub
Retail stock traders and investors require responsive real-time price updates, portfolio performance visualizations, and low-latency order execution simulation without database performance bottlenecks.
Built a high-performance React/TypeScript frontend with dynamic price charts and responsive tabular data views, connected to a Spring Boot microservice architecture powered by Apache Kafka event streaming, Redis caching, and WebSockets.
Enterprise Core Banking & Multi-Level Approval Platform
Modular banking system with multi-tier transaction approval workflows and OpenAPI standards
Complex enterprise banking transactions required strict multi-role approval state machines, standardized data mapping, file import validation, and audited workflow processing without degrading query speed.
Architected modular Spring Boot RESTful services with JPA/Hibernate query optimizations, Jmix administrative interface integration, PostgreSQL relational database, and OpenAPI 3.0 documentation.
SaaS Admin & Analytics Dashboard Implementation
Responsive React/TypeScript administrative UI with data visualization and REST API integration
Legacy back-office interfaces suffered from poor mobile responsiveness, sluggish table pagination, and fragmented API error handling.
Built a modern React + TypeScript dashboard utilizing Tailwind CSS for responsive styling, TanStack Table for efficient data grid pagination/filtering, and custom chart components.
RESTful API & Identity Authentication Gateway
Secure OAuth2 API gateway with Keycloak integration, Redis rate-limiting, and Docker deployment
Microservice ecosystems face fragmented security policies, repetitive authentication logic, and lack of standardized rate limiting across service endpoints.
Implemented a Spring Boot API Gateway with Keycloak JWT validation, Redis token caching, and Docker Compose orchestration.
Technical Arsenal & Core Competencies
Categorized technical depth across backend development, database systems, microservices, and DevOps tooling.
React & Frontend UI
Modern component architectures, responsive web interfaces, and state management.Java & Backend Architecture
Enterprise Java frameworks, REST APIs, and backend service integration.Databases & Infrastructure
Relational data stores, caching layers, and asynchronous event streaming.DevOps & Tooling
Version control, containerized deployment, and API specifications.How I Work With Clients
A transparent, developer-driven freelance engineering process from project scope to final delivery.
Scope & Requirement Alignment
Clarify project objectives, technical requirements, target deliverables, and timeline milestones.
Architecture & Interface Design
Design clean API contracts (OpenAPI/Swagger), database schemas, and intuitive component structures.
Iterative Engineering & Testing
Develop robust React components and Spring Boot services with continuous verification and quality assurance.
Delivery & Documentation
Deploy clean, maintainable code with thorough documentation, API specs, and handoff support.
Career History & Track Record
Engineering experience across enterprise banking modules, microservices, and API platforms.
React/TypeScript & Java/Spring Boot Freelance Developer
Independent Freelance Practice — Remote / FreelanceDelivering end-to-end web applications, React frontend implementations, Spring Boot REST APIs, and database engineering solutions for clients.
- Developed responsive React/TypeScript frontend applications, financial dashboards, and SaaS administrative interfaces.
- Built scalable Java 21 & Spring Boot RESTful APIs following contract-first OpenAPI specifications.
- Designed relational database schemas in PostgreSQL, utilizing JPA/Hibernate for optimized query execution.
- Integrated identity security with Keycloak (OAuth2/JWT) and asynchronous streaming pipelines with Kafka & WebSockets.
- Provided bug fixing, UI refactoring, performance tuning, and third-party API integrations for existing client codebases.
Java & Spring Boot Developer
Enterprise Core Banking Platform — Remote / Project ContractContributed to building enterprise-level banking systems featuring multi-tier transaction approval workflows and high-performance APIs.
- Built and optimized RESTful APIs using Spring Boot adhering to OpenAPI standards.
- Developed multi-level approval workflows and transaction state machines for enterprise business logic.
- Designed complete CRUD logic, data mapping, file import validation, and standardized error handling pipelines.
- Optimized PostgreSQL queries and JPA/Hibernate mappings to maintain sub-second response times under peak request loads.
Engineering Principles & Values
React & TypeScript UI Engineering
Crafting responsive, component-driven web interfaces, SaaS dashboards, and tabular applications with clean state management, Vite, and Tailwind CSS.
Java & Spring Boot Backend Systems
Architecting robust RESTful microservices, JPA/Hibernate ORM mappings, multi-level approval workflows, and OpenAPI 3.0 specs.
Full-Stack Integration & APIs
Seamlessly connecting React frontends with Spring Boot backends, PostgreSQL databases, Keycloak OAuth2 authentication, and third-party APIs.
Performance & Database Optimization
Optimizing PostgreSQL database queries, implementing Redis caching layers, and troubleshooting complex application bottlenecks for production reliability.
Have a project or system that needs building?
Whether you need a React/TypeScript frontend, a Java/Spring Boot backend, a dashboard interface, API integration, or bug fixing for an existing product — let's align on your requirements.