
Sergey Y
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Experiencia laboral
Full-Stack Web Developer
Freelancer.com • Freelance
May 2022 - Present • 4 yrs 2 mos
Full-Stack Web Developer | Freelance Worked as a freelance Full-Stack Web Developer, designing, developing, deploying, and maintaining custom web applications and e-commerce platforms from concept to production. Specialized in building modern, responsive, and high-performance websites using React, JavaScript (ES6+), Node.js, Express.js, and MongoDB. Developed scalable REST APIs, optimized database architecture, implemented authentication systems, and integrated third-party services for real business projects. Key responsibilities included: • Full-cycle web application development from planning to deployment • Frontend development with React, HTML5, CSS3, and modern JavaScript • Backend development using Node.js and Express.js • REST API architecture and secure API integration • MongoDB database design, optimization, and data synchronization • Authentication and authorization using JWT • Payment gateway integration and order processing systems • Google SEO optimization, Schema.org structured data, XML sitemaps, robots.txt, and metadata optimization • Performance optimization including lazy loading, image optimization, caching, and Core Web Vitals improvements • Responsive UI/UX implementation for desktop, tablet, and mobile devices • Development of custom administration panels for content and product management • Third-party API integrations, automation tools, and synchronization systems • Deployment, maintenance, debugging, and long-term technical support Throughout my freelance work I have successfully delivered complete business solutions including custom e-commerce platforms, inventory management features, product synchronization systems, advanced search and filtering, SEO optimization, and user account functionality. My focus is always on writing clean, maintainable, scalable code while delivering reliable and user-friendly applications that help businesses grow.