Karl S.

Top Rated Plus Full Stack Mobile App Developer | Top 3% UpWork Talent | Flutter | Kotlin | Swift | React, Node.js, AWS | Building Scalable Digital Experiences

I’m a passionate and detail-oriented Full Stack Developer with over 10 years of experience crafting high-quality Web and Mobile applications for startups, enterprises, and agencies worldwide. I specialize in building end-to-end solutions using modern technologies and frameworks — from beautiful, responsive UIs to robust, scalable backend systems.

💡 Tech Stack Highlights:
Frontend:Flutter (Dart), React-Native, Kotlin, Swift, React.js, Tailwind CSS, TypeScript

Backend: Node.js (Next.js, NestJS), GraphQL, REST APIs

Database:, MySQL, MSSQL, MongoDB, Firebase, Google Cloud

DevOps/Cloud: Docker, GitHub Actions, AWS (EC2, S3, Lambda)

Tools: Git, Jira, Notion, Postman, CI/CD, WebSockets, Stripe, OAuth2

What I Offer:
Full-cycle Development from concept to Deployment

Clean, maintainable, and scalable code

Mobile-friendly, SEO-optimized, and fast-loading applications

API integrations (Stripe, Twilio, Firebase, third-party REST/GraphQL)

Agile collaboration with clear communication and on-time delivery

I’ve completed a wide range of freelance projects: custom dashboards, SaaS platforms, eCommerce sites, API backends, mobile-first apps, and admin panels. Whether you're looking to launch an MVP, optimize an existing product, or scale your system, I bring technical expertise and business acumen.

✅ Why Clients Choose Me:
Strong work ethic & attention to detail

Fast learner and great problem solver

Transparent and clear Communication

Available for one-time projects or long-term collaboration

Let’s build something amazing together. Drop me a message — I’d love to hear about your project!