Hire the Best React.js Developers in Kolkata, IN

As a Software Developer with ⭐ 4 years of experience, I specialize in creating dynamic websites and web applications for small and medium-sized businesses. Whether you're looking to secure projects, showcase your services, or launch an online store, I have the expertise to bring your vision to life. Why work with me? ✔️ Backend Expertise: Experienced with Node.js, Express and C# ✔️ React.js , Angular.js Next.js: Building modern, responsive, and dynamic websites ✔️ Database: MySQL, PostgreSQL and MongoDB ✔️ Expert in Front-End Development: Proficient in HTML5, CSS3, JavaScript, TypeScript, Bootstrap, Tailwind and material UI ✔️ Full Project Management: From design to deployment, I handle everything with clear communication ✔️ Timely Delivery: Focused on meeting deadlines while ensuring top-notch quality Let’s work together to bring your project to life and create a strong online presence that delivers results!

Need to turn an AI or SaaS idea into a reliable production product—not another fragile prototype? I’m a senior full-stack and AI integration developer with 14 years of experience building scalable SaaS applications, AI-powered platforms, internal tools, automation systems, and customer-facing products. I work across architecture, frontend, backend, databases, third-party integrations, security, and deployment. This allows me to take ownership of the complete development process—from technical planning and prototyping to production launch and ongoing improvement. 🧠 AI Integration and Automation I can help you build the following: • AI agents and chatbots using OpenAI, Claude, LangChain, and LlamaIndex • RAG assistants that answer questions from documents and business data • Voice AI agents using Retell AI and Vapi • Customer support, appointment booking, and lead qualification workflows • AI tools connected to CRMs, calendars, payment systems, and internal APIs • n8n, Make, Zapier, and custom workflow automations • Response validation, fallback handling, citations, and human escalation flows 💻 SaaS and Full-Stack Development I build and improve: • Multi-tenant SaaS platforms • Next.js and React applications • Supabase and PostgreSQL backends • Dashboards, portals, marketplaces, and administration systems • Subscription and payment workflows using Stripe, Square, and PayPal • Authentication, permissions, RLS policies, and role-based access • REST APIs, GraphQL APIs, webhooks, and real-time features • Production deployments using Vercel, AWS, Docker, and cloud infrastructure 🔍 Production Reviews and Migrations I also help founders and teams improve applications created with AI coding tools, low-code platforms, or previous development teams. This can include: • Architecture and scalability reviews • Security and database audits • Supabase RLS validation • Codebase cleanup and bug fixing • Performance optimization • Lovable-to-Supabase or Vercel migrations • Deployment and production-readiness reviews Why clients work with me: • 14 years of hands-on engineering experience • Complete frontend-to-backend product ownership • Strong understanding of business workflows and architecture • Practical production experience with AI—not only prototypes • Clear communication and structured progress updates • Focus on security, maintainability, and long-term scalability Core stack: Next.js, React, TypeScript, Node.js, Python, Supabase, PostgreSQL, MongoDB, OpenAI, Claude, LangChain, Retell AI, Vapi, n8n, Stripe, PayPal, AWS, Vercel, and Docker. Tell me what you are building, your current technology stack, and the main technical challenge. I’ll help you identify the safest and most efficient path to production. Thanks, Dipanjan Dutta

𝗧𝗼𝗽-𝗥𝗮𝘁𝗲𝗱 | 𝗧𝗼𝗽 𝟐% 𝗼𝗳 𝗙𝗿𝗲𝗲𝗹𝗮𝗻𝗰𝗲𝗿𝘀 | 𝟏𝟎𝟎+ 𝐁𝐢𝐥𝐥𝐞𝐝 𝐇𝐨𝐮𝐫𝐬 | 𝟐𝟎+ 𝗦𝗮𝘁𝗶𝗳𝗶𝐞𝐝 𝗖𝗹𝐢𝗲𝗻𝐭𝐬 Hi! I'm a 𝗦𝗲𝗻𝗶𝗼𝗿 𝗙𝘂𝗹𝗹 𝗦𝘁𝗮𝗰𝗸 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗲𝗿 with 5+ years of experience building high-performance web and mobile applications that are scalable, secure, and user-friendly. I specialize in 𝗥𝗲𝗮𝗰𝘁, 𝗥𝗲𝗮𝗰𝘁 𝗡𝗮𝘁𝗶𝘃𝗲, 𝗡𝗲𝘅𝘁𝗝𝗦, 𝗧𝘆𝗽𝗲𝗦𝗰𝗿𝗶𝗽𝘁, 𝗝𝗮𝘃𝗮𝗦𝗰𝗿𝗶𝗽𝘁, 𝗡𝗼𝗱𝗲𝗝𝗦, 𝗘𝘅𝗽𝗿𝗲𝘀𝘀, 𝗛𝗧𝗠𝗟𝟱, 𝗖𝗦𝗦𝟯, 𝗧𝗮𝗶𝗹𝘄𝗶𝗻𝗱 𝗖𝗦𝗦, 𝗙𝗶𝗿𝗲𝗯𝗮𝘀𝗲, 𝗦𝘂𝗽𝗮𝗯𝗮𝘀𝗲, 𝗣𝗼𝘀𝘁𝗴𝗿𝗲𝗦𝗤𝗟, 𝗠𝗼𝗻𝗴𝗼𝗗𝗕, 𝗔𝗪𝗦, and 𝗔𝗜-powered applications. I help startups, agencies, and businesses transform ideas into production-ready products—from MVPs to enterprise applications. Whether you need a modern SaaS platform, an AI-powered application, a responsive website, or a cross-platform mobile app, I can take your project from concept to deployment. ### My Expertise ✅ React, NextJS & TypeScript Development ✅ React Native & Expo (Android & iOS) ✅ Full Stack Development (NodeJS, Express, REST APIs, GraphQL) ✅ AI Integration (OpenAI, ChatGPT, Claude, Gemini, LangChain, LangGraph, MCP, RAG) ✅ Firebase, Supabase, MongoDB, PostgreSQL & MySQL ✅ AWS, Vercel, Docker & CI/CD ✅ Authentication (JWT, OAuth, Firebase Auth) ✅ Real-time Applications (SocketIO, WebSockets) ✅ Stripe, PayPal & Third-party API Integrations ✅ Figma to Pixel-Perfect Responsive UI ✅ Performance Optimization, SEO & Core Web Vitals ✅ Play Store & App Store Deployment ### What I Deliver • Pixel-perfect implementation from Figma, Adobe XD, or PSD designs • Fast, responsive, and scalable web and mobile applications • Clean, maintainable, and well-documented code • REST API and backend architecture development • AI chatbot, AI assistant, and workflow automation integrations • Dashboard, CRM, SaaS, Marketplace, Booking System, and Admin Panel development • Cross-platform React Native applications for Android and iOS • Firebase and Supabase integration with real-time databases and authentication • CI/CD pipelines, cloud deployment, and production support • Bug fixing, performance optimization, and long-term maintenance I believe in writing clean, scalable code, maintaining clear communication throughout the project, and delivering solutions that create real business value. My goal is to build products that are reliable, fast, easy to maintain, and ready to grow with your business. If you're looking for a dependable React, React Native, NextJS, NodeJS, Full Stack, or AI Developer who can own the entire development lifecycle, from planning and architecture to deployment and ongoing support, I'd be happy to discuss your project.

I build AI-powered products and mobile applications that actually ship — cleanly architected, production-ready, and built to scale. Most developers can write code. Fewer can design a system that holds up under real load, integrates AI meaningfully, and is still maintainable six months later. That's where I focus. My background is unusual for a developer: I'm pursuing a PhD in Quantum Computing at Bengal Engineering and Science University while working full-time as a senior AI and mobile developer. That research foundation — built on top of an MS in Applied Physics — means I approach AI systems differently. I don't just plug in APIs. I understand the models, their limits, and how to build around them reliably. What I specialise in: • Flutter mobile apps (iOS & Android) — from MVP to production, with clean state management and Firebase or Node.js backends • AI systems — RAG pipelines, LLM-powered features, document intelligence, and AI assistants using OpenAI, Gemini, LLaMA, Mistral, and Qwen • Backend architecture — Node.js and Python APIs, multi-tenant SaaS platforms, payment integrations, and third-party service wiring • Full-stack SaaS — end-to-end ownership from database schema to deployed product I've built across healthcare, fintech, logistics, travel, and edtech — which means I understand that good software isn't just technically correct. It has to work for real users, in real workflows, under real constraints. If you have a product idea, an MVP to validate, or an existing system that needs AI capabilities added — I'm happy to talk through it. I'll tell you honestly what will work, what to skip, and what to build first. Send me a message and let's figure out if we're a good fit.

Bot & AI Geek | 90%+ Job Success Score | 5+ Years of Experience Specialised in: OpenClaw Agent Setup N8N | Zapier | Make| OpenClaw Frontend: Next.js, React.js, jQuery, AJAX Backend: Node.js, Python AI & Bots: AI Integration, Instagram Bots, Telegram Bots Web Scraping: Advanced Web Scraping Techniques

I don’t just write code. I work as a product partner helping refine ideas, suggesting improvements, and ensuring every project is aligned with your business goals. Clients value me for delivering on time and for my ability to take ownership of the product vision, not just complete tasks. Along the way, I’ve built AI chatbots with 50K+ users, AI agents that reduced workload by 60%, and full-stack SaaS products generating $2M in monthly revenue. I’ve also developed a product selected by Y Combinator and another that was acquired within 2 years. My unique edge is combining AI innovation with full-stack development — building scalable products, intelligent automations, and platforms that deliver measurable business outcomes. 🔹 Core Expertise ✅ AI Product Development: GPT-powered apps, chatbots, AI agents ✅ Automation & Integration: n8n, Zapier, Make, workflow orchestration, API integrations ✅ Frontend: React.js, Vue.js, React Native, TypeScript, HTML5, CSS3, Bootstrap ✅ Backend: Node.js, PHP, Laravel, WordPress ✅ Databases: MongoDB, MySQL, PostgreSQL ✅ Cloud & DevOps: AWS, Azure, GCP, DigitalOcean ✅ Design & Prototyping: Figma 📈 Success Snapshot ✅ Built chatbots with 50K+ users and AI agents → saved teams 20+ hours weekly ✅ Helped scale SaaS platforms from MVP to 50,000+ users with strong uptime ✅ Managed a SaaS product generating $2M monthly revenue ✅ Built a product selected by Y Combinator and another acquired in 2 years ✅ Delivered automation pipelines with n8n/Zapier/Make → improved efficiency by 60% 🔹 Why Clients Work With Me ✅ Blend of full-stack engineering + AI expertise ✅ Proven record of building products that generate revenue, get funded, and get acquired ✅ Take ownership: I contribute ideas, refine features, and improve product vision — not just execute tasks ✅ Always deliver on time, with a transparent, milestone-driven workflow ✅ Balance of technical depth + product mindset, ensuring solutions that grow with your business 👉 If you’re looking for a developer who can build scalable apps, integrate AI, and act as a true product partner with ownership, let’s connect. For Search Optimization: AI Developer, Full-Stack Developer, SaaS Developer, Node.js Developer, React.js Developer, Vue.js Developer, Chatbot Developer, AI Agent Developer, Automation Developer, n8n Expert, Zapier Specialist, Make Expert, Workflow Automation, GPT Integration, AI SaaS Developer, Backend Developer, Frontend Developer, Cloud Developer, AWS Developer, GCP Developer, Azure Developer, Figma UI/UX