Rajat K.

I build and maintain web platforms for startups, SaaS companies and product teams - from a Figma file, an idea or an existing codebase through to a production deployment on AWS. My core stack is MERN (MongoDB, Express, React, Node.js) with TypeScript, Next.js and PostgreSQL. What I am working on now - Enterprise platform development on the MERN stack, as a technical partner working inside a client's own engineering team: React front ends, Node.js and Express APIs, MongoDB data models and continuous feature delivery. - Healthcare and telehealth software built to HIPAA requirements: EMR workflows for a clinical practice, SOAP note documentation, e-prescribing, lab ordering through an API, continuous glucose monitor data from Dexcom, audit trails, Medicare compliance requirements, Stripe onboarding and AWS deployment. - Front-end engineering and UI testing for applications that need to keep performing as usage and features grow. Full-Stack Web and SaaS Applications - SaaS platforms and MVPs - Customer portals, dashboards, admin panels and reporting - CRM-style and internal business platforms - Authentication, roles and permissions - Subscription and payment flows with Stripe - REST APIs and third-party API integrations - Responsive React and Next.js interfaces built from Figma designs Ecommerce - Custom ecommerce and subscription commerce platforms - BigCommerce stores, including custom theme work - B2B wholesale ordering for trade customers - Product catalogues, customer accounts, delivery scheduling and payment integration Backend, Database and Cloud - Node.js, Express and TypeScript services - PostgreSQL and MongoDB data modelling - API architecture and integrations - AWS deployment - Performance optimisation, production debugging and modernisation of existing applications AI Features in the Applications I Build I am extending my full-stack work into AI: OpenAI API integrations, and AI agents that call an application's own APIs to carry out business workflows. The same discipline applies as to any other feature - clear data models, permissions, error handling and a proper deployment. Selected Work - Enotria: B2B ecommerce for a UK wine and spirits supplier, with trade accounts, wholesale ordering and delivery management. - Dr. Nancy: a healthcare and ecommerce platform for a medical weight-loss practice, with consultation scheduling and a supplement store. - A telecom customer portal combining plan comparison, device sales, digital SIM services and account self-service. - A BigCommerce furniture store with custom Stencil theme work and HubSpot integration. - A specialty coffee subscription platform with quiz-based recommendations and recurring deliveries. Industries I Have Built For - Healthcare and telehealth - SaaS - Ecommerce and retail: consumer subscriptions, furniture, B2B wine and spirits supply - FinTech - Telecom - Sales and CRM platforms - Enterprise applications End-to-End Product Development I am most useful when you need an engineer who understands the whole product, not just one layer of it: Figma or idea, then architecture, React / Next.js, Node.js, database, APIs, AWS and production That lets me make practical decisions across the stack and avoid unnecessary complexity between frontend, backend and infrastructure. How I Work 1. Understand: your business goals, users, workflows, existing codebase and constraints. 2. Architect: the technical approach, integrations and development plan. 3. Build: focused milestones with clean, maintainable code. 4. Test and optimise: functionality, APIs, responsiveness, security and performance. 5. Deploy: from development to a reliable production environment. 6. Improve: ongoing development, optimisation and new features. Why Work With Me - Full-stack engineer since 2011 - Strong React, Next.js, Node.js and TypeScript, with MERN in production - Frontend, backend, database and cloud ownership - Comfortable joining an existing codebase and team, or starting an MVP from scratch - I work through Matrix Marketers, so larger builds can draw on a wider team when needed - Completed 7,389 hours on Upwork - Clear communication and practical technical decisions If you are building a SaaS platform, a healthcare application, an ecommerce system or a modern web product, send me your requirements, designs or existing application and I will propose a plan to take it to production.