Gokul S.

Full-Stack Developer with 5+ years of experience building and scaling SaaS products, B2B platforms, travel and booking systems, internal tools, and AI-powered applications. 3,000+ hours on Upwork, including a 14-month engagement building and scaling a production platform. I work across the full product stack - from React/Next.js interfaces and backend APIs to PostgreSQL, third-party integrations, authentication, payments, and AI/LLM features. I focus on building products that are clean, maintainable, secure, and ready to grow beyond the MVP stage. ------------------------------------------------------- What I Build ------------------------------------------------------- • B2B SaaS platforms - authentication, roles, subscriptions, multi-tenancy • AI-powered SaaS - LLM integrations, RAG, AI workflows, and automation • Travel & booking platforms - search, inventory, bookings, payments • Production-ready MVPs designed to scale without unnecessary rewrites • Admin dashboards, internal tools, and customer portals • REST APIs, webhooks, real-time features, and third-party integrations • Existing product stabilization, refactoring, testing, and performance improvements ------------------------------------------------------- Tech Stack ------------------------------------------------------- Frontend: React.js, Next.js, TypeScript, JavaScript, HTML5, CSS3, Tailwind CSS Backend: Node.js, Express.js, NestJS, Python, FastAPI AI / LLM: OpenAI, Claude, LLM APIs, RAG, LangChain, LangGraph, AI Agents, Prompt Engineering Database: PostgreSQL, MySQL, MongoDB, Redis APIs & Integrations: REST APIs, WebSockets, Webhooks, Stripe, Payment Gateways, CRM integrations, External APIs, Email Services Security: JWT, Sessions, OAuth, RBAC, Rate Limiting, Audit Logs DevOps & Infrastructure: Docker, AWS, CI/CD, Git, GitHub ------------------------------------------------------- Full-Stack Coverage ------------------------------------------------------- Architecture: Modular system design, API architecture, scalability, performance optimization APIs: REST APIs, WebSockets, Webhooks, API integrations, clear service contracts Data: Database schema design, migrations, indexing, query optimization Integrations: Stripe, payment gateways, CRMs, email services, and third-party APIs Security: JWT, sessions, OAuth, RBAC, rate limiting, audit logs Product Engineering: Authentication, roles and permissions, subscriptions, multi-tenancy, real-time functionality, testing, debugging, and refactoring ------------------------------------------------------- Working Model ------------------------------------------------------- Long-term product engagements are my default. I can work independently as a full-stack engineer or collaborate with additional engineers from my team when the scope requires it. I take ownership across the stack so the frontend, backend, database, and integrations stay consistent as the product evolves from MVP to v1 and beyond. Whether you're building a new SaaS product, adding AI capabilities to an existing platform, or stabilizing a production codebase, I focus on delivering scalable, secure, maintainable solutions that create real business value - not just prototypes.