Kaustubh J.Private profile: Upwork shows its earnings only to signed-in members, so we check it every few weeks, not daily. MRR here is a rough estimate (Upwork's six-month earnings ÷ months active). Last read Nov 5, 2026.

Hii! I’m a Full-Stack Developer specializing in React.js, Flutter, scalable backend systems, and blockchain integrations. I design and build production-ready applications with clean architecture (MVVM, MVC), optimized APIs, and secure Web3-enabled ecosystems that scale seamlessly across mobile and web platforms. Over the past few years, I’ve developed apps, dashboards, and smart contracts that connect efficiently through modern cloud infrastructures, focusing on maintainability, scalability, and performance. What I Can Do for You Frontend Development (React.js + Next.js) Build responsive, component-driven web apps using React and TypeScript. Integrate REST & GraphQL APIs with efficient state management (Redux, Zustand, Context API). Follow modular design and reusable UI patterns with TailwindCSS or Material UI. Optimize rendering and routing for high-performance dashboards or admin panels. Mobile App Development (Flutter + Dart) Develop cross-platform mobile apps with MVVM architecture for clean separation of concerns. State management using Provider, Riverpod, or Bloc. Integrate REST APIs, local databases, authentication flows, and push notifications. Modular, scalable architecture for enterprise-level apps. Backend Development (Node.js + Express + MongoDB / MySQL) Design and deploy RESTful APIs and microservices with secure authentication and caching. Implement JWT / OAuth2 authentication, error handling, and validation layers. Build real-time systems using WebSockets / Socket.IO. Deploy on AWS, Render, or DigitalOcean with CI/CD integration. Blockchain & Smart Contracts Create and deploy tokens on Solana, BSC, and Polygon. Write and audit smart contracts (ERC-20, SPL) using Remix, Hardhat, and Anchor. Integrate blockchain APIs and SDKs into web or mobile apps. Implement multichain bridging with Wormhole SDK for token transfers. Architecture & Refactoring Migrate legacy projects into modular, testable architectures. Apply MVVM for Flutter and Clean Component Structure for React/Next.js. Modular API layers for Node.js backends. Reusable widgets, services, and hooks for maintainability. Tech Stack Languages: Dart, JavaScript, TypeScript, Python, Solidity Frontend: React.js, Next.js, TailwindCSS, Material UI Mobile: Flutter (MVVM), Dart Backend: Node.js, Express.js, REST, GraphQL Databases: MongoDB, MySQL, PostgreSQL, Firebase Blockchain: Solana, Binance Smart Chain (BSC), Polygon Tools: Git, Docker, Postman, VS Code, Remix IDE, Hardhat, Metaplex Architectures: MVVM, MVC, Clean Architecture, Microservices Notable Projects RTW Coin: Multichain token deployed on Solana & BSC with Wormhole bridge integration. TopSell App: Flutter app deployed on Play Store with REST API backend and MVVM structure. CCTPL UpChecker: React + Node.js uptime monitoring platform with alert automation. Reproserve Web Showcase: React-based client portfolio website with modular UI and SEO optimization. Why Work With Me I combine frontend precision, backend reliability, and blockchain innovation to deliver complete digital solutions. My approach is based on clean code, scalability, and transparent communication, ensuring smooth collaboration and future-ready systems. Whether it’s a full-stack web dashboard, mobile app, or decentralized platform, I build software that grows with your business. Let’s bring your idea to life, from architecture and API design to frontend deployment and production scaling.