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Karthikeyan S

I am currently working as a Backend Software Engineer at WithU (UK), where I design and scale robust serverless architectures for a global fitness and wellness platform. My focus lies in delivering highly available and low-latency backend systems, leveraging AWS services to optimise performance and cost-effectiveness. I am known for owning end-to-end backend modules and have been recognised with the "Best Employee of the Quarter" award for delivering mission-critical features ahead of deadlines.

My expertise includes building scalable microservices with Node.js, TypeScript, and GraphQL, and deploying serverless infrastructures with AWS Lambda, DynamoDB, and Cognito. I’ve also worked on real-time multiplayer gaming platforms and fintech integrations using Web3 SDK and WebSockets. I’m experienced with CI/CD automation, REST APIs, MongoDB, Redis, React, React Native, and more – making me well-versed in full-stack as well as backend-heavy development.

Across roles, I have successfully led projects, mentored juniors, and collaborated closely with cross-functional teams using Agile methodologies. A proactive and fast learner, I consistently ensure quality and timely delivery. I’m now looking forward to new international opportunities—especially in Germany—where I can further challenge myself and make impactful contributions to innovative backend systems.

  • Role

    Senior Backend Engineer

  • Years of Experience

    7.4 years

Skillsets

  • Event-driven
  • Next.js
  • Python
  • Redis
  • Socket.IO
  • TypeScript
  • API Gateway
  • Claude api
  • CloudWatch
  • CodePipeline
  • distributed
  • JavaScript
  • Gemini
  • Genkit
  • Groq
  • Hugging Face
  • Lambda
  • Observability
  • REST
  • S3
  • SQL
  • Websockets
  • MongoDB
  • CI/CD
  • Cloudfront
  • Cognito
  • Copilot
  • Cursor
  • Docker
  • DynamoDB
  • Express.js
  • GraphQL
  • Microservices
  • AWS
  • MySQL
  • Node.js
  • OpenAI
  • RabbitMQ
  • react
  • React Native
  • Terraform
  • Claude code
  • Colyseus
  • GCP

Professional Summary

7.4Years
  • Jan, 2023 - Present3 yr 9 months

    Senior Backend Engineer

    10XU
  • Jul, 2022 - Jan, 2023 6 months

    Backend Engineer

    Diagnal Technologies
  • May, 2021 - Jun, 20221 yr 1 month

    Backend Engineer

    Alter.Game
  • Feb, 2019 - May, 20212 yr 3 months

    Full Stack Developer

    LeagueX Gaming

Work History

7.4Years

Senior Backend Engineer

10XU
Jan, 2023 - Present3 yr 9 months
    Architected and led delivery of the serverless backend powering Mvmnt, a fitness platform serving thousands of concurrent users globally, on AWS Lambda, DynamoDB, AppSync GraphQL and Cognito at 99.9% uptime. Cut live-session latency from 200ms to under 5ms by replacing cloud round-trips with a purpose-built LAN WebSocket server, removing the associated streaming infrastructure cost entirely. Improved scalability under launch-day load, raising peak throughput 30% through autoscaling, Redis caching and an event-driven fan-out redesign; instrumented CloudWatch monitoring and alerting across services. Built the CI/CD pipeline (CodePipeline, automated testing, staged rollouts with rollback), cutting release cycle time 40%; own API contracts, SLAs, security reviews and on-call runbooks, unblocking 5 cross-team initiatives per quarter.

Backend Engineer

Diagnal Technologies
Jul, 2022 - Jan, 2023 6 months
    Built serverless GraphQL APIs (AppSync, VTL resolvers, DynamoDB) with IAM-scoped authorisation for Enhance, a media-streaming platform delivering content for enterprise broadcasters across Asia. Reduced API latency 50% (180ms to 90ms) by rewriting resolvers to batch DynamoDB access and eliminate N+1 query patterns. Cut Lambda cold-start impact 80% with a scheduled warm-up strategy, and moved read paths into VTL resolvers to bypass Lambda entirely, lowering compute cost 40%.

Backend Engineer

Alter.Game
May, 2021 - Jun, 20221 yr 1 month
    Engineered real-time multiplayer backends with Socket.IO and Colyseus, holding authoritative game state across concurrent match rooms with low-latency event delivery. Improved API responsiveness 45% via Redis caching and query optimisation on MongoDB hot paths. Integrated Web3/Ethereum SDKs for wallet authentication, token and NFT flows, with server-side signature verification and replay protection. Rebuilt multiplayer onboarding, increasing new-player signups 18% in 90 days; mentored 2 junior engineers through design review and pairing.

Full Stack Developer

LeagueX Gaming
Feb, 2019 - May, 20212 yr 3 months
    Shipped end-to-end features across Node.js, Express, React and React Native for a real-money fantasy-sports platform. Automated operations dashboards and workflows, removing 20 hours of manual effort per week; defined platform-wide API standards for authentication, validation and rate limiting.

Major Projects

3Projects

Kaivon Labs Crypto Market-Making Bot

Jan, 2025 - Present1 yr 9 months
    Founded Kaivon Labs and built a production market-making bot quoting two-sided liquidity against live capital, running unattended 24/7. Implemented async ingestion of L2 order-book feeds in Python, maintaining local book state under continuous high-frequency updates with sub-millisecond quote recalculation. Engineered risk controls, inventory skew, position limits, automated kill switches and fill reconciliation plus metrics and alerting for live PnL and exposure.

Mail Wise AI Email Analysis

Jan, 2025 - Dec, 2025 11 months
    Built a full-stack email-intelligence service using Gemini via Genkit for deliverability scoring, disposable-provider and fake-address detection; shipped as both a public REST API and an interactive web tool on Firestore.

OpenClaw / Clio AI Content Automation

Jan, 2025 - Dec, 2025 11 months
    Built a multi-model orchestration platform running a daily automated video pipeline: async task queues coordinate LLM, TTS and video-generation stages, fed by trend-ingestion pipelines from X.

Education

  • PG Programme, Full Stack Engineering

    Birla Institute of Technology and Science, Pilani

  • M.Sc. Software Systems

    Kongu Engineering College (2019)