Building scalable SaaS platforms, enterprise applications, and AI-powered web solutions using React.js, Next.js, Node.js, TypeScript, PostgreSQL, AWS, Docker, OpenAI, and Claude AI.
6+
Years of Experience
20+
Production Projects
15+
Technologies Worked With
Background
Senior Full Stack Engineer with 6+ years of experience architecting, developing, and delivering scalable SaaS platforms, enterprise applications, AI-powered solutions, and B2B/B2C marketplaces. Strong expertise in React.js, Next.js, Node.js, TypeScript, PostgreSQL, AWS, Docker, OpenAI, Claude AI, Stripe, and multi-tenant SaaS systems.
Experienced in end-to-end software delivery — from requirement analysis and architecture design to API development, cloud deployment, and production support. Recent work includes AI chatbot SaaS platforms with Stripe billing, RAG-based document processing, and large-scale marketplace systems.
Expertise
Career
Senior Software Developer
Jun 2025 – Present · Remote · Full-time
Architecting and developing scalable SaaS platforms, enterprise applications, and marketplaces. Designing multi-tenant architectures, compliance workflows, inventory management, and analytics. Leading feature delivery, code reviews, and engineering best practices.
Full Stack Developer
Sep 2024 – May 2025 · Full-time
Developed logistics and operations platforms with dashboards, reporting, and analytics. Built REST APIs and backend services using Node.js and PostgreSQL. Implemented data visualization with Chart.js and ApexCharts.
Full Stack Developer
Feb 2024 – Aug 2024 · Full-time
Developed AI-powered chatbot SaaS solutions using OpenAI APIs and RAG workflows. Implemented Stripe subscriptions, recurring billing, invoicing, and webhook automation. Built multi-tenant chatbot solutions with usage-based plans.
Software Developer
Dec 2022 – Jan 2024 · Full-time
Developed secure communication platforms using React.js, Node.js, WebRTC, and Socket.IO. Implemented JWT, OAuth2, and RBAC-based security systems. Built scalable real-time communication services.
Software Development Mentor / Teaching Assistant
Jan 2022 – Nov 2022 · Full-time
Mentored students in JavaScript, React.js, Node.js, and software development fundamentals. Conducted code reviews, debugging sessions, and project guidance.
Software Developer
Feb 2020 – Dec 2021 · Full-time
Developed business applications, dashboards, and REST APIs. Designed backend services and integrated third-party systems to optimize business operations.
Portfolio
Production systems built across AI automation, SaaS platforms, marketplaces, and enterprise applications.
Problem
Businesses needed a scalable multi-tenant AI chatbot product with subscription billing and real-time messaging.
Solution
Built a full multi-tenant platform with Stripe subscription billing, recurring payments, invoicing, webhook-based subscription management, usage tracking, and real-time chat.
Problem
Organizations needed to automate extraction and processing of data from unstructured documents at scale, eliminating manual data entry.
Solution
Automated OCR, document analysis, structured data extraction, validation, and semantic search using OpenAI and Claude AI integrations.
Problem
A B2B/B2C marketplace needed multi-vendor storefronts, compliance workflows, inventory, and logistics management.
Solution
Built multi-tenant marketplace with seller storefronts, compliance and approval workflows, inventory management, payment integrations, and logistics tracking.
Problem
Enterprise teams needed a unified platform for project planning, task management, approvals, reporting, and analytics.
Solution
Developed an Angular + .NET workflow platform supporting project planning, multi-level approvals, task tracking, reporting dashboards, and business analytics.
I am open to remote full-time and contract opportunities where I can contribute to scalable SaaS platforms, AI-powered products, and enterprise applications.
Contact
Open to remote full-time roles, contract work, and consulting opportunities. I respond within 24 hours.
Senior Full Stack Engineer
me@nirajkumar.in
Location
India · Open to Remote Opportunities
linkedin.com/in/niraj-kumar-dev
Portfolio
nirajkumar.in
Phone / Call
+91 94538 00108
+91 94538 00108