Karthick SG — Senior Full-Stack Developer

Senior Full-Stack Developer with 5+ years of hands-on experience designing, developing, and maintaining production-grade applications using the MERN stack (MongoDB, Express.js, React, Node.js). Expertise ranges from building reusable, responsive React UI components with consistent cross-browser UX to developing secure, scalable RESTful APIs and modeling performance-optimized MongoDB databases. Experienced in deploying AI-driven enhancements and integrations, including production-grade MCP servers and a privacy-first Telegram AI assistant (ensuring strict data privacy and responsible usage). Proven track record of improving reliability, troubleshooting production issues, and automating CI/CD pipelines to cut release cycles by ~83%. A collaborative engineer dedicated to code reviews, shared coding standards, and comprehensive API documentation.

Core Skills & Technologies

Node.js · Express.js · NestJS

React · JavaScript · TypeScript

MongoDB (Schema & Query Tuning)

RESTful API Design & JWT/Session Auth

Git-based Collaborative Workflows

CI/CD (GitHub Actions) · Docker

AI Integration (Claude API & Ollama)

Data Privacy & Responsible AI Usage

Azure Cloud (Functions, Logic Apps, Bicep)

AWS Cloud (S3, Lambda, CloudFormation)

Microservices & Event-Driven (Kafka)

Reusable UI Components & UX Alignment

Clean Code · Unit Testing · Code Reviews

API & Component Documentation

Professional Experience

Senior Software Engineer — Full Stack (MERN & AI)

Dec 2022 – Present · 3+ yrs

Techversant Infotech Pvt. Ltd.

MERN Stack · React · Node.js · Express.js · MongoDB · Azure · AWS · GitHub Actions

Full-Stack Development: Design, develop, and maintain scalable web applications using the MERN stack; build reusable, responsive React UI components ensuring consistent UX across browsers/devices.
Secure API & Auth Design: Develop secure, scalable RESTful APIs in Node.js/Express, integrating them with React workflows and implementing JWT and session-based authentication patterns.
MongoDB Management: Model and manage database schemas in MongoDB, writing performance-aware queries and setting indexes to optimize data retrieval speeds.
AI-Enabled Feature Delivery: Integrate AI services (e.g., Claude AI API, local LLMs) into existing workflows for intelligent automation, ensuring data privacy and responsible usage guidelines.
Quality & Production Reliability: Write clean, testable code, participate in peer code reviews, troubleshoot production issues, and automate CI/CD pipelines via GitHub Actions to slash release cycles by ~83%.
Collaboration & Documentation: Collaborate with product, design, and QA to refine requirements, estimate effort, and maintain thorough documentation for APIs, component libraries, and architecture decisions.

Software Engineer — Full Stack (React & Node.js)

Aug 2021 – Nov 2022 · 1 yr 4 mo

AES Technologies India Pvt. Ltd.

MERN Stack · React · Node.js · Express.js · MongoDB · JWT · OAuth 2.0 · Singpass API · Git

React UI Development: Delivered responsive React UIs, optimizing rendering and state management while ensuring cross-browser UX consistency.
Secure API Development: Engineered high-availability REST APIs (Node.js/Express) integrated with Singapore's national Singpass API, employing JWT and OAuth 2.0 standards.
Reusable Libraries: Published reusable component packages to simplify frontend workflows, standardizing UI patterns and accelerating feature delivery.
Production Troubleshooting: Resolved critical system bugs and improved performance by collaborating with product, design, and QA teams.
Engineering Standards: Wrote clean, testable code, participated in collaborative Git-based code reviews, and maintained technical documentation.

Software Developer — MERN Stack

Jun 2020 – Jul 2021 · 1 yr 2 mo

DDL Tech Solutions Pvt. Ltd. (Startup)

MERN Stack · React · Node.js · Express.js · MongoDB · JWT · REST APIs

MERN Stack Development: Built end-to-end enterprise web applications using React for front-end and Node.js/Express for backend, owning code from schema design to UI integration.
MongoDB Optimization: Modeled MongoDB schemas and optimized NoSQL queries for high-frequency billing workloads, boosting data retrieval performance.
Reusable APIs: Engineered a reusable billing engine and secure RESTful APIs with role-based JWT access control to standardize customer integrations.

Notable Projects

MCP Expense Tracker (AI-Powered)

Node.js · TypeScript · MCP SDK · Claude AI API · SSE

Designed and shipped an AI-driven service integrating Claude AI as a natural-language interface for transaction tracking. Defined custom tool schemas, optimized API endpoints, and ensured secure SSE transport.

Open-Source npm Packages (3 Published)

React · Angular · TypeScript · npm

Authored and published 3 production npm packages, including react-satti-chart (React bar chart). Showcases deep knowledge of building reusable React components and UX consistency.

Telegram AI Assistant — Local LLM + n8n

n8n · Ollama · Qwen2.5 · Telegram Bot API · MCP

Engineered a private, zero-cloud-cost AI assistant utilizing a local LLM via Ollama and n8n workflows. Demonstrates secure API integration, local AI automation, and strict adherence to data privacy.

Multi-Tenant Platform Backend

Node.js · MongoDB · Azure · AWS S3 · Kafka · Git

Architected backend services for a secure multi-tenant cloud application. Focused on database schema optimizations, REST API security, Git-based version control, and clear technical documentation.

Education & Certifications

Master of Computer Applications (MCA)

KLN College of Engineering, Madurai · 2018–2020

B.Sc. Information Technology

Sourashtra College of Arts & Science, Madurai · 2014–2017

AI Engineering — MCP, RAG, Multi-Agent Orchestration (Self-directed, 2025–26)

Open-source contributor — 3 published npm packages · 1,000–5,000+ downloads