Senior Frontend Engineer with 7+ years of experience specializing in high-traffic web platforms, performance optimization, and cross-platform desktop/mobile engineering. Currently building independent products and open-source software with a focus on React 19, Next.js 15, TypeScript, C++ Native Addons (Electron), and AI-assisted engineering workflows.
Open-Source Cross-Platform Media Player
- Hybrid video playback engine combining a modern web UI with custom C++ Native MPV bindings (
node-addon-api/libmpv) inside Electron for hardware-accelerated, ultra-low-latency video playback. - 100% client-side architecture with zero server-side media processing, in-memory search indexing, and EPG caching for large playlists.
- 🔗 Website: webframeplayer.com
Real-Time FinTech Market Data Concept
- Resilient market data architecture featuring fallback providers, retry policies, and a three-layer caching strategy to manage API rate limits and outages.
- Real-time chart rendering via WebSockets and Lightweight Charts with 90%+ test coverage using Vitest.
- 🔗 Live Demo: phintech.furkankoseoglu.com
⚖️ Hakkımne.com
Financial & Legal Calculation SaaS Engine
- High-performance legal and financial calculation platform built with Next.js App Router, TypeScript, PostgreSQL, and Prisma ORM.
- Multi-tier server-side caching and dynamic revalidation reducing API response times below 300 ms.
- 🔗 Website: hakkimne.com
Cross-Platform Fitness Ecosystem
- Offline-first application for iOS, Android, and Web using React Native, Expo, and Zustand; data secured via Supabase Row-Level Security (RLS).
- Automated PR reviews and Acceptance Criteria verification using LLM workflows, supported by 1,800+ unit (Jest) and E2E (Playwright) test scenarios in GitHub Actions CI/CD.
- Core & Web: React 19, Next.js 15 (App Router), TypeScript, JavaScript (ES6+), HTML5, CSS3, Tailwind CSS
- Mobile & Desktop: React Native, Expo, Electron, C++ Native Addons (node-addon-api / libmpv)
- State & Backend: Zustand, TanStack Query, Supabase (RLS, Edge Functions), PostgreSQL, Prisma ORM, WebSockets, REST APIs
- Testing & QA: Vitest, Jest, Playwright E2E, React Testing Library, TDD
- AI & DevOps: AI Agent Workflows (LLMs), GitHub Actions CI/CD, Docker, Git Flow
