Ceyhun Türkmen

Profile

Full Stack Developer with concurrent expertise across Next.js, ASP.NET Core, and Node.js ecosystems, having designed and deployed 8+ live commercial platforms. Independently built critical production system components across e-commerce, enterprise SaaS, and EdTech — including payment infrastructure (iyzico), real-time notifications (SignalR), background jobs, and Redis caching. Delivered high business-value features such as interactive exam engines, automated certificate generation, RBAC + TOTP/2FA authentication for TAV Security, and Meta CAPI server-side analytics with canvas-based product customization for e-commerce projects. Manages the full software lifecycle from requirements to CI/CD deployment; consistently achieves Lighthouse 95+, SEO 100/100.

Technical Skills

FrontendReact, Next.js (SSR/SSG/ISR), TypeScript, Redux Toolkit, Tailwind CSS, Bootstrap, shadcn/ui, Framer Motion, GSAP

BackendASP.NET Core, Node.js, Express.js, RESTful API, SignalR, JWT, RBAC, TOTP/2FA, IHostedService

DatabasePostgreSQL, MongoDB, MySQL · EF Core, Prisma, Sequelize, Mongoose · Repository/UoW Pattern

DevOps & InfraDocker, Docker Compose, CI/CD (GitHub Actions), Nginx, Linux, VPS, PM2, Redis

LanguagesTypeScript, JavaScript (ES6+), C#, C, C++

Integrationsiyzico, Twilio SMS, SendGrid, Cloudinary, Horoz Kargo, Meta CAPI, Google Analytics, Nodemailer

AI & TestingAnthropic Claude API, Google Gemini, Prompt Engineering · xUnit, Moq, Jest, Supertest

ArchitectureClean Architecture, SOLID, Rate Limiting, Health Checks, i18n (next-intl), Serilog, FluentValidation, PDF/DOCX generation

Performance & SEOCore Web Vitals, WebP/AVIF, Lazy Loading, Code Splitting, JSON-LD Structured Data, Technical SEO, Sitemap/robots.txt

Securitybcrypt, HttpOnly JWT, KVKK/GDPR, Helmet.js, GeoIP Session Validation, Signed Cloudinary Upload, Zod Validation

Experience

Freelance Full Stack Developer Remote | 2024 – Present

Designed, developed, and deployed 8+ production-ready commercial platforms across e-commerce, enterprise training, and marketplace categories.
Improved backend response times through PostgreSQL/MySQL index strategies and query optimization; established systematic error tracking with Serilog structured logging.
Built scalable backend architectures implementing SignalR real-time notifications, Redis caching, and IHostedService background jobs.
Delivered end-to-end development of Meta Conversions API (CAPI) server-side ad tracking, Horoz Kargo logistics integration, and iyzico payment infrastructure.
Gained recognition on Bionluk by appearing on Rising Stars and Most Loved Freelancers lists, standing out for client satisfaction.

Core Stack: Next.jsASP.NET CoreNode.jsPostgreSQLMySQLPrismaRedisDockerNginxVPS

TAV Security – Corporate Training & Exam Platform (TavAkademi) Enterprise | 2025

TAV Private Security Services · Airport Security Personnel Digital Training Infrastructure

Met enterprise security requirements with JWT-based RBAC and Google Authenticator TOTP/2FA for Admin / Trainer / Personnel roles; reinforced with GeoIP-based session validation.
Developed interactive exam modules with a polygon editor for object-marking baggage inspection simulation (X-Ray tools: filter, negative, layer merging).
Automated training operations with automated certificate generation (DOCX template engine + PDF-lib + QR code), Puppeteer browser automation, and Excel bulk user import.
Built a question pool engine for theoretical, visual, and mixed exam types; exam security (fullscreen enforcement, tab-switch detection); and Recharts performance reporting.

Stack: ReactRedux ToolkitViteNode.jsExpress.jsMySQLSequelizeJWTSpeakeasy (TOTP)PuppeteerPDF-libDocxtemplaterRedisGeoIP

E-Commerce Platforms 6+ Active Commercial Projects

IsPool · BalkoLüx · Moda Perde · NowArt Plicell · RosallieBaby · BarScarf

Delivered end-to-end secure payment infrastructure with product & order management, admin panel, and iyzico payment integration (installment support, sandbox/production).
Built ad conversion tracking via Meta Conversions API (server-side), Google Analytics 4, and SEO infrastructure with JSON-LD structured data; dynamic sitemap and robots.txt generation.
Developed real-time shipment tracking via Horoz Kargo logistics API and a canvas-based product customization tool (drag-and-drop, layer management, image export).
Met Turkey-specific localization requirements: cascading city/district/neighborhood address system, national ID verification, and KVKK-compliant cookie management.
Achieved Core Web Vitals targets through Next.js SSR and image optimization (WebP/AVIF, lazy loading, code splitting); consistently scored Lighthouse 95+.

Stack: Next.js 15ReactTypeScriptPrismaMySQLNextAuth.jsCloudinaryiyzicoDockerVercel

Bulursa – Freelance Marketplace Platform Team Project | 2024 – Ongoing

Contributed to sprint-based Agile (Scrum) development with iterative task planning and delivery.

Featured Projects

Jhun.com.tr – AI Assistant-Powered Multilingual Portfolio Next.js · SSG · Anthropic Claude + Google Gemini · next-intl (TR/EN)

Personal corporate portfolio and blog platform. Full TR/EN bilingual support via next-intl; AI assistant powered by Anthropic Claude API + Google Gemini fallback answering visitor questions about CV, projects, and experience in real time; keyword-based quick response + LLM fallback architecture; Lighthouse 100/100 SEO score.

Universal Appointment System – Multi-Tenant Booking API ASP.NET Core · C# · PostgreSQL · EF Core · Redis · SignalR · Docker · xUnit

Scalable multi-tenant appointment management system for healthcare, beauty, education, and legal sectors. JWT/RBAC with Provider / Receiver / Business / Admin roles, real-time notifications via SignalR, Redis caching and SignalR backplane, IHostedService SMS reminder background job, Twilio SMS + SendGrid email, built-in .NET 8 rate limiting, PostgreSQL + Redis health checks. Fully documented RESTful API with Swagger; xUnit & Moq tests; GitHub Actions CI/CD pipeline.

IsPool – Occupational Safety E-Commerce Platform Next.js · Prisma · PostgreSQL · iyzico · Cloudinary · Canvas Design Tool

B2C + B2B platform for PPE and occupational safety equipment. Canvas-based product customization tool (react-rnd drag-and-drop, layer management, html-to-image export), AI-powered background removal (remove-bg API), Horoz Kargo logistics integration, and custom manufacturing order flow.

VANET Cyber Attack Simulator OMNeT++ · SUMO · C++

Graduation project — academic simulation modeling cyber attacks such as DoS, message tampering, and identity spoofing in vehicular ad-hoc networks (VANET).

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