Parambir K.

Most clients find me in one of two situations. Either they have an idea and no code yet, or they have an app that looks fine in a demo but gets slow or breaks once real users arrive. I work on both, and I stay with the product after launch. Top Rated | 100% Job Success | 42 jobs | 8,100+ hours | $100K+ earned on Upwork I'm a full-stack developer with 10+ years of experience. I mostly build SaaS products, AI features, and real-time web apps with React, Next.js, Node.js, Python, and Ruby on Rails. A few things I've worked on Ad Genius : A live analytics platform for performance marketing. The pages were slow because the same calculations were repeated in the database and in the app, and data was fetched one request after another. I traced the repeats, simplified how data moves through the system, and made the fetches run in parallel. Stack: Next.js, Python, BigQuery, PostgreSQL, Sentry, Vercel, AWS. JigsawML : A tool that reads a code repository and draws it as dependency and call graphs, with both technical and business views of the architecture. You can drill down into any part, and AI helps explain what the code does. Stack: Python backend, WebSockets, React, React Flow. NymCard : A fintech platform for card issuing, payments, money movement, and lending, built from many small services (microservices) that process transactions in real time. Stack: Kafka, RabbitMQ, Redis, Kubernetes, REST and GraphQL APIs. What I can help with • SaaS and web apps: multi-tenant products (many customers on one system), user roles, Stripe billing and Stripe Connect, admin dashboards, real-time features with WebSockets • AI features: Claude, OpenAI, Gemini, LangChain, RAG (AI that answers from your own documents and data), AI agents, n8n automation • Backend and APIs: Node.js, NestJS, Python, FastAPI, Django, Ruby on Rails, PostgreSQL, BigQuery, Redis, REST, GraphQL, third-party integrations, webhooks • Frontend: React, Next.js, Vue, TypeScript, Tailwind, Strapi for content management • Cloud and delivery: AWS, Google Cloud, Azure, Docker, Kubernetes, CI/CD, Vercel, Sentry for error tracking How I work I ask the uncomfortable questions early. If your plan is too big for your budget or timeline, I will say so in the first week, not the third month. I write code that the next developer can read, I post clear updates, and I tell you honestly when something is going to slip. Many of my contracts last several months, and clients usually describe me as collaborative, a clear communicator, and reliable. I work with clients in the US and Europe and can overlap with your working hours. Best fit if you: • are building a SaaS or AI product from scratch • have a half-finished app that needs a developer to take it over • have an app that works for a few users and needs to handle many more • need someone to own the technical side without daily supervision Send me a short message with what you're building, where it stands today, and when you need it. I'll reply with questions and an honest view on whether I'm the right fit. Warm Regards, Tags:- #SaaS Development #Full Stack Development #React.js #Next.js #Node.js #Python #Ruby on Rails #AI Integration #API Development #Database Optimization #Cloud Infrastructure #Microservices #WebSockets #PostgreSQL #AWS