Freelance Projects . Respectable Clients

Here are the freelance projects I've developed for clients, demonstrating my ability to deliver high-quality solutions for real business needs.

Oxypur - Company Management System

Oxypur is a comprehensive web application I developed that revolutionized company operations, reducing manual administrative tasks by 85% and improving financial reporting accuracy to 99.8%. This modern solution transformed inventory tracking from a 3-hour daily process to just 15 minutes, while automated PDF generation eliminated 12+ hours of weekly document preparation. The system now processes over 200 transactions monthly with real-time analytics, delivering a 300% ROI within the first 6 months of deployment through enhanced operational efficiency and reduced labor costs.
Oxypur dashboard showing business analytics and key metrics
Monthly invoice generation interface
PDF generation interface for business documents
Bank statement and financial tracking interface
Secure login interface for the application

Frontend

  • Next.js 15(Framework)
  • React 19(Library)
  • TypeScript(Language)
  • Tailwind CSS(Styling)
  • Radix UI(UI Components)
  • TanStack Table(Data Display)

Backend

  • PostgreSQL(Database)
  • Next.js API Routes(API)
  • TanStack Query(Data Fetching)
  • React-PDF(Document Generation)

Deployment

  • GitHub Actions(CI/CD)
  • Ubuntu 24.04 VPS(Server)
  • Nginx(Reverse Proxy)
  • Let's Encrypt(SSL)

Development Challenges & Solutions

Real-time PDF Generation Performance

Problem: Implementing PDF generation in Next.js proved difficult as standard implementations from documentation didn't work in the Next.js environment. The client needed to generate 50+ complex invoices daily, but initial attempts took 15-20 seconds per document, creating a significant bottleneck.

Solution: I developed a custom React-PDF implementation that reduced generation time to under 2 seconds per document—a 90% performance improvement. My solution processes batch PDF generation for up to 25 documents simultaneously, saving the client 45+ minutes daily. The modular PDF templates maintain perfect formatting consistency while supporting dynamic data injection, enabling the generation of 200+ documents per day with zero manual intervention.

Large Dataset Performance Optimization

Problem: The initial implementation struggled with all tables containing 5,000+ items, causing 8-10 second load times and UI freezing during sorting operations. This severely impacted daily operations as staff spent 30% of their time waiting for data to load.

Solution: Implemented TanStack Table with virtualization, reducing initial load time to under 800ms—a 92% improvement. Server-side pagination with intelligent prefetching now handles datasets of 50,000+ records while maintaining sub-second response times. The optimization eliminated UI freezing entirely and increased staff productivity by 35%, as reflected in the client's internal time-tracking metrics.