Mariya S.

$1M+ earned on Upwork. 25+ years, 700+ projects, and deep JavaScript/TypeScript expertise across React, Next.js, Node.js & NestJS. I build and scale SaaS, web apps, automation, APIs, and complex platforms from architecture to production.

👋 I’m a veteran Senior Full-Stack JavaScript/TypeScript Engineer, Full Stack JavaScript Developer, React Developer, Node.js Developer, and Web Developer with 25+ years of experience building scalable web applications, SaaS platforms, automation systems, browser extensions, and enterprise-grade JavaScript products.

I work across the full product lifecycle - from architecture and UI development to backend APIs, cloud infrastructure, integrations, performance optimization, and production support. My core stack includes React, React.js, Next.js, Node.js, NestJS, TypeScript, Vue.js, Angular, PostgreSQL, MongoDB, Redis, AWS, Docker, and serverless technologies.

Over the years, I’ve delivered 700+ projects across SaaS, eCommerce, Fintech, Web-to-Print, EdTech, Healthcare, CRM, AI automation, marketplaces, analytics, and enterprise platforms.

🏆 RESULTS & EXPERIENCE

✔ 25+ years in full stack development and web engineering
✔ 700+ web, SaaS, React, Node.js, and automation projects delivered
✔ Systems handling 10M+ API requests per month
✔ 30+ applications scoring 90–100 in Lighthouse audits
✔ Backend performance improvements of up to 50%
✔ Production experience with startups, scaling products, and enterprise systems
✔ Advanced AWS serverless, event-driven, and real-time architecture
✔ CI/CD and monorepo workflows that accelerate delivery and simplify maintenance

⚡ FRONTEND / REACT DEVELOPMENT

As a Senior React Developer and Frontend Developer, I build fast, maintainable interfaces for SaaS platforms, dashboards, marketplaces, internal tools, and customer-facing applications.

My frontend expertise includes:

• React 18, React.js, Next.js 14+, Vue.js, Angular, TypeScript
• SPA, SSR, ISR, PWA, and responsive web application development
• Tailwind CSS, Material UI, SCSS, Bootstrap, and reusable UI systems
• Complex dashboards, analytics interfaces, charts, and data visualization
• Storybook, design systems, reusable component libraries, and UI architecture
• Nx, Turborepo, Module Federation, and micro frontend architecture
• Core Web Vitals, Lighthouse optimization, bundle reduction, and frontend performance • Mobile-first development and React Native integrations • Chrome extensions, browser extensions, content scripts, background services, and extension APIs • Puppeteer, Playwright, browser automation, scraping workflows, and automated testing