Razorpay subscriptions, Google Play Billing, verified webhooks and server-side pricing.
SOFTWARE ENGINEER · VIT VELLORE
I build things
that ship.
I'm Karthikeyan, a computer science student who enjoys building dependable backend systems, useful products, and the infrastructure that gets them into people's hands.
CURRENT FOCUS
Backend / Product / Cloud
Backend / Product / Cloud
K.
01 — 04
Curiosity in. Working software out.
Handled store setup, Data Safety, content rating, review fixes and release verification.
Worked on authentication hardening, database migration and AWS deployment troubleshooting.
Built the backend for Awaaz, a VR presentation coach with AI-assisted feedback.
01 / EXPERIENCE
Work with
real-world impact.
I like owning a problem across boundaries, from an API or interface to deployment and production debugging.
MAY 2026 — PRESENT
SDE Intern
VIIAN GenomicsWorked across Recollia, a medical learning product for students and doctors. My work covered payment and subscription services, authentication, cloud infrastructure, web/mobile product flows, and the Android release process.
- Built 9 of 11 payment endpoints across Razorpay and Google Play Billing, including subscription lifecycle actions and HMAC-verified webhooks.
- Implemented JWT verification across tutor and companion services to close an authorization gap.
- Supported the Supabase Auth to Cognito migration and Google OAuth 2.0 sign-in with PKCE.
- Migrated PostgreSQL workloads to AWS RDS with pgvector and operated ECS/Fargate, RDS, CloudFront, Cognito and related AWS services.
- Built 42 Next.js pages, 57 React components and 35 Flutter screens; reduced exam API payloads by 22 MB and first-screen assets by 43%.
- Drove the Google Play production release process, including store listing, compliance, review fixes and release verification.
FastAPINext.jsFlutterPostgreSQLAWSPayments
OCT 2024 — JUN 2025
App Developer Intern
Voxvertex Solutions · New DelhiHelped build a Flutter professional-networking app, delivering 54 of 60 screens across authentication, multi-role signup, profiles, filtering, events and chat.
Set up app structure using GoRouter, Provider and ScreenUtil, and integrated REST APIs with Dio. The app was used in investor demonstrations.
FlutterDartREST APIsProviderGoRouter
JUN 2024 — APR 2025
Software Developer · Senior Core Member
CodeChef-VITContributed browser automation features to Perry, the VTOP extension, and built Flutter screens for Kalculate, a student utility application.
JavaScriptBrowser AutomationFlutter
02 / SELECTED PROJECTS
Built to solve
something.
Selected work with live product links where available and public repositories for projects I can share.
P01LIVE PRODUCT · BACKEND · MOBILE
SUBSCRIPTIONVERIFIED
Recollia · Product Engineering
A medical learning product for MBBS students and doctors. I built payment and subscription endpoints for Razorpay and Google Play Billing, worked on authentication and AWS infrastructure, and drove the Android production release process.
FastAPIPostgreSQLRazorpayPlay BillingAWS
P02LIVE WEBSITE · SIDE PROJECT
MUNNAR°
SWARG
RESIDENCYSTAY · EXPLORE · UNWIND
RESIDENCYSTAY · EXPLORE · UNWIND
Swarg Residency
A website for a holiday apartment in Munnar, designed to present the stay, spaces and location clearly, with direct enquiry and booking flows for prospective guests.
Web DevelopmentResponsive UIBooking Enquiries
P03VR · AI · HACKATHON
A↗
PRACTISE · FEEDBACK · IMPROVE
✳ 1ST PLACE · CODE2CREATE 6.0
Awaaz · VR Presentation Coach
A VR public-speaking rehearsal experience. I built the backend that connects the experience to AI-assisted speech feedback and stores session-level performance analytics.
Express.jsSupabaseOpenAI APIUnity
P04BACKEND · PAYMENTS · TESTING
RESIDENT PORTAL / BILLING
Society Management System
A multi-tenant backend for resident onboarding, role-based access, facility booking and recurring maintenance billing. Integrated Razorpay with server-side order creation and HMAC signature verification, then covered the API with automated tests.
Node.jsExpress.jsMongoDBRazorpayJest
P05BROWSER AUTOMATION
VTOP / QUICK ACTIONS
Perry · VTOP Extension
A browser extension that automates repetitive academic workflows using asynchronous operations and targeted DOM manipulation, reducing friction in everyday VTOP tasks.
JavaScriptHTMLCSSBrowser APIs
Private repository · details available on request
P06MOBILE · VEHICLE INSPECTION
Vehicle inspection
CAT Fix
A Flutter vehicle-inspection app concept with structured forms for tires, battery, exterior, brakes and engine checks. The repository documents the current UI and clearly separates planned features from implemented work.
FlutterDartGoRouterMobile UI
MORE CODE
More projects on GitHub
Explore the Refyne.ai backend, conference management system, Flutter projects and smaller experiments.
03 / TOOLKIT
Comfortable across
the stack.
01
Backend & APIs
FastAPI, Node.js, Express.js, REST APIs, SQLAlchemy, Pydantic, Redis
02
Web & Mobile
TypeScript, JavaScript, React, Next.js, Flutter, Dart, React Native, Three.js
03
Data & Storage
PostgreSQL, pgvector, MongoDB, MySQL, SQLite, Supabase
04
Cloud & Reliability
AWS ECS/Fargate, ECR, ALB, RDS, S3, CloudFront, Cognito, CloudWatch, IAM, Docker, CI/CD
05
Security & Payments
JWT, OAuth 2.0, PKCE, RBAC, HMAC-SHA256, webhooks, idempotency, Razorpay, Google Play Billing
06
Languages & Testing
TypeScript, JavaScript, Python, SQL, Dart, C++, Java, Jest, pytest
EDUCATION
Vellore Institute of Technology
B.Tech. Computer Science and Engineering
IBM · DevOps FundamentalsIBM · Agile & Design ThinkingNVIDIA · Fundamentals of Deep LearningVIT-TBI · Concept to Company
04 / CONTACT
Have a good
problem to solve?
I'm interested in engineering opportunities where I can build, learn quickly, and take ownership.
Let's talk ↗KS.