Rajan Singh

Backend Developer

I build scalable systems. Real-time queues, AI integrations, and cloud-backed APIs.

Available for full-time roles.

io.on('connection', (socket) => {
  socket.on('join-queue',
    async (data) => {
      // add to BullMQ
      await queue.add('token', data);
      io.emit('queue-updated',
        await getQueue());
    }
  );
});

io.on('connection', (socket) => {
  socket.on('join-queue',
    async (data) => {
      // add to BullMQ
      await queue.add('token', data);
      io.emit('queue-updated',
        await getQueue());
    }
  );
});

A Quick Hello

Projects

Healthcare

Live ↗GitHub ↗

SmartCare

A clinical coordination platform with real-time queue tracking, automated medication reminders, and multi-role access control.

Live clinic queue with Socket.IO. Patients see token updates in real time, no polling.
Medication reminder engine via BullMQ and Redis. Async jobs keep the main API thread unblocked.
Nightly cron precomputes adherence snapshots. Dashboard reads are O(1) at any scale.
Role-based access for Patient, Doctor, and Caregiver with isolated data views.
Cashfree payment integration and AWS S3 medical record uploads.

Node.jsTypeScriptExpressPostgreSQLRedisBullMQSocket.IOPrismaReactAWS S3

Real-Time

GitHub ↗

ChatApp

A real-time group chat app with AI smart replies, file sharing, and automated message archival.

Multi-room WebSocket architecture spanning Global Chat, DMs, and custom rooms, each with JWT-protected handshakes.
Google Gemini integration for smart reply suggestions and message autocomplete.
Secure file uploads to AWS S3 via multer pipeline.
Midnight cron archives messages in a SQL transaction. Active table stays lean.

Node.jsExpressMySQLSequelizeSocket.IOAWS S3Google GeminiJWT

Finance

GitHub ↗

ExpensAI

An AI-powered personal finance app with auto-categorization, a premium tier, and Cashfree payments.

Google Gemini auto-categorizes expenses from description. No dropdown needed.
Full CRUD with paginated queries and atomic DB transactions to keep totals in sync.
End-to-end premium flow: Cashfree payment, order verification, and isPremium flag update.
AWS S3 expense export and AI financial insights for premium users.

Node.jsExpressMongoDBMongooseAtlasGoogle GeminiCashfreeAWS S3JWT

Like what you see? Get in touch.

Tech Stack

Backend

Node.jsExpress.jsTypeScriptREST APIsSocket.IOBullMQnode-cron

Databases

MySQLPostgreSQLMongoDBRedisSequelizePrismaMongooseAtlas

Cloud & DevOps

AWS EC2AWS RDSAWS S3VercelRenderSupabaseDocker

Frontend

ReactViteTailwindCSSVanilla JS

Integrations

Google Gemini AICashfreeBrevoJWTbcryptGit & GitHub

About me

I'm a backend developer who spent the last year building production-grade systems instead of following tutorials. My work spans real-time WebSocket architecture, background job processing with BullMQ and Redis, AI integrations with Google Gemini, and cloud deployments across AWS (EC2, RDS, S3), Vercel, Render, and Supabase.

I'm looking for a backend developer role where I can own APIs and services end to end, and I'm available to start immediately.

Location: Haryana, India
Availability: Full-time, on-site or remote
Focus: Node.js, TypeScript, PostgreSQL

Let's Connect

I'm actively looking for backend developer roles. If you're hiring or just want to talk tech, my inbox is open.

Send Me a Message

LinkedIn ↗GitHub ↗WhatsApp ↗