Muhammad Saadullah S.

Top Rated Full-Stack Next.js | MERN Developer with 100% Job Success I help startups and businesses build, improve, and scale production-ready SaaS web apps using Next.js, React, Node js, Express.js, MongoDB, TypeScript, Redis, Socket IO, Twilio, and AI/API integrations. With 4+ years of production experience, I have worked with Y-Combinator backed, Misk Launchpad backed, bootstrapped startups, and independent clients across Upwork. My work includes SaaS platforms, CRMs, marketplaces, messaging systems, automation workflows, dashboards, and AI-powered web applications. ✅ Building SaaS MVPs from scratch ✅ Developing full-stack web apps using Next.js, React, Node.js, and MERN ✅ Fixing bugs and improving existing React, Next.js, and Node.js apps ✅ Adding AI agents, AI automation, OpenAI, Claude, Gemini, and DeepSeek integrations ✅ Building AI-powered chatbots, voice workflows, and backend automations ✅ Integrating Twilio, SendGrid, Stripe, Chargebee, OpenAI, and third-party APIs ✅ Building real-time apps using Socket IO, Redis, BullMQ, webhooks, and background jobs ✅ Optimizing existing codebases for performance, scalability, and maintainability ✅ Deploying apps on Vercel, AWS, GCP, Hetzner, Docker, PM2, and Nginx Core Expertise: 👉 Frontend: Next.js, React, TypeScript, JavaScript, Tailwind CSS, Redux Toolkit 👉 Backend: Node.js, Express.js, Python, FastAPI, REST APIs, webhooks 👉 MERN Stack: MongoDB, Express.js, React, Node.js 👉 AI Integration: OpenAI API, Claude API, Gemini, DeepSeek, AI agents, prompt engineering 👉 AI Automation: LangChain, n8n, Make, Zapier, MCP servers, workflow automation 👉 Voice AI: Vapi, ElevenLabs, OpenAI Whisper, Twilio voice agents, Telnyx voice AI 👉 Databases: MongoDB, PostgreSQL, MySQL, Redis, Elasticsearch 👉 Real-Time Systems: Socket IO, WebSockets, BullMQ, background jobs, webhook processing 👉 DevOps: Docker, GCP, AWS, Hetzner, Vercel, Nginx, PM2, CI/CD Projects: ➔ SmartAlto (YC-backed Real Estate CRM) Worked on a production CRM platform for real estate skip tracing and lead management using React, Node.js, Express.js, MongoDB, Twilio, SendGrid, Chargebee, Docker, and GCP/GKE. ➔ Messaging SaaS Platform Built and managed a messaging platform using Next.js, MongoDB, Redis, BullMQ, Socket IO, Twilio webhooks, PM2, Nginx, and Hetzner deployment. ➔ UGC Marketplace for Content Creators Built a marketplace connecting content creators with businesses using Next.js, Redux Toolkit, Supabase, REST APIs, media uploads, and responsive frontend workflows. ➔ Electron Desktop Applications Built desktop productivity and media applications using Electron, React, Tailwind CSS, local databases, and background task scheduling. ➔ AI/API Automation Workflows Built AI-powered workflows, API integrations, automation systems, and backend services for SaaS products using Node.js, Python/FastAPI, OpenAI-style APIs, and webhook-based architectures. What Clients Say: "Great & professional work done. I would like to work long term. Thanks." "He is the best person I hired on Upwork because he has good communication skills, he is patient, he maturely takes criticism and makes swift corrections, he guides you through the journey of actualizing your dream project. Lastly, I feel comfortable working with him." Why Work With Me? ✦ Top Rated with 100% Job Success on Upwork ✦ Real production experience, not just demo projects ✦ Clear communication and regular progress updates ✦ Strong experience with SaaS, AI integrations, APIs, and real-time systems ✦ Clean, scalable, and maintainable code ✦ Startup-friendly execution with practical technical decisions Need a reliable developer to build, fix, scale, or add AI to your SaaS product? Let’s discuss your project.