Karthik Mahadev

Full-Stack Developer | React.js, Next.js, Node.js, TypeScript | REST APIs & Real-Time Systems | Building Production-Ready Web Applications · Thanjavur, Tamil Nadu, India

As a Full Stack Engineer, I am driven by a deep ambition to achieve mastery in crafting robust and scalable systems. I thrive on the autonomy of independently architecting end-to-end solutions, constantly seeking to deepen my expertise and deliver impactful results through self-reliance and a methodical approach.

Experience

Full Stack Engineer

Freelance · Aug 2026 – Present

Not yet confirmed

• The Relish Jar — Coimbatore-based Food Brand | Freelance Full-Stack Project
• • Independently designed and developed a full-stack e-commerce website end-to-end, from UI design through production rollout, using Next.js, TypeScript, Tailwind CSS, and Framer Motion.
• • Built a complete product catalog and shopping cart system with Supabase/PostgreSQL, implementing Row-Level Security (RLS) to separate public product data from protected order and customer data.
• • Integrated Razorpay payments with server-side order creation, webhook-based payment verification, signature validation, and idempotent order persistence to prevent duplicate orders.
• • Developed a custom admin dashboard with session-based authentication, enabling the client to manage products, track orders, and update fulfillment status independently.
• • Implemented an automated transactional email workflow using Resend for successful order notifications and integrated website analytics to monitor visitor behavior and product engagement.
• • Deployed the application on Vercel with GitHub-based CI/CD, and currently handling final production configuration, domain setup, and payment gateway approval.

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Founding Full-Stack Developer

Binary Budds · Dec 2025 – Jul 2026

Not yet confirmed

• • Owned full-stack development across web (Next.js) and mobile (React Native/Expo) as a founding engineer, shipping features for three distinct user roles — parents, drivers, and school administrators.
• • Designed and built a Super Admin Impersonation system — JWT-based middleware, dynamic school-context resolution, and a secure two-cookie session model letting super admins safely view any school's dashboard
• • Explored observability tooling (Sentry, Uptime Kuma, Grafana + Prometheus + Loki) for API monitoring and alerting, containerized via Docker
• • Took the React Native (Expo) driver and parent apps from feature-complete to a published release on the Google Play Store
• • Diagnosed and resolved a memory leak on production DigitalOcean droplets that was degrading long-running uptime, stabilizing the GPS ingestion service
• • Designed a high-throughput GPS ingestion architecture — a dedicated Node.js TCP listener on DigitalOcean parsing live Teltonika AVL device data, with a dual-write pattern (InfluxDB for time-series history, Supabase for live map state) to keep the primary database performant under continuous location pings

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Software Developer

origa.market (formerly Origa Lease Finance) · Jan 2025 – Sep 2025

Not yet confirmed

• Spearheaded performance optimization efforts across the platform, boosting Google Lighthouse scores from ~50% to 96% by removing render-blocking resources, lazy-loading components, and eliminating unused CSS/JS.
• Continued to integrate and optimize Algolia for enhanced product search and real-time filtering, improving user journey efficiency.
• Led the migration of the entire frontend codebase from React 18 to React 19, resolving compatibility issues, upgrading package dependencies, and ensuring zero downtime.
• Owned full-cycle feature development — from ideation to production deployment — maintaining high standards in scalability, performance, and maintainability.

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Software Developer Trainee

origa.market (formerly Origa Lease Finance) · Jun 2024 – Dec 2024

Not yet confirmed

• Developed and implemented the entire cart functionality for a B2B e-commerce platform, supporting both guest and logged-in user flows with persistent cart data post-login.
• Integrated PhonePe as a third-party payment gateway for seamless checkout, including address management and order processing.
• Wrote modular and scalable frontend code, handled component state management, and ensured high code quality via GitHub version control and structured commit practices.

What drives their work

The Architect

Designs and constructs robust systems from the ground up.

Karthik's superpower

You excel at translating complex requirements into well-structured, high-performing technical architectures and seeing them through to completion.

How Karthik works

You are best suited for roles where you can take significant ownership of the technical architecture and development lifecycle within a transparent and innovative team.