💰 PaytmNext Wallet App

A full-stack Paytm Wallet clone built with Next.js (TypeScript), Express (TypeScript), PostgreSQL, and Prisma ORM, featuring:

• OnRamp transactions (bank to wallet)
• Peer-to-peer (P2P) wallet transfers
• Transaction history
• UI state management with Jotai atoms
• CI/CD via Docker & GitHub Actions, deployed to AWS EC2

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🚀 Features

• 🔐 Authentication

  • Secure login/signup with NextAuth.js

• 🏦 /dashboard

  • Displays authenticated user dashboard

• 💸 /transfer

  • Simulate bank-to-wallet OnRamp transaction
  • View current wallet balance

• 👥 /p2ptransfer

  • Transfer Paytm Wallet balance to another user
  • List of registered users

• 📜 /transactions

  • View complete OnRamp and P2P transaction history

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⚙️ System Architecture

🧠 Architecture Overview

• Frontend/Backend: Next.js (TypeScript) app styled with Tailwind CSS
• Webhook Server: Node JS - Express (TypeScript) server receives simulated bank callbacks for OnRamp success
• Database: PostgreSQL accessed through Prisma ORM
• Monorepo: Managed with Turborepo
• CI/CD: Docker + GitHub Actions for builds and deployment to EC2
• State Management: Jotai atoms for global state (e.g., sidebar highlight)

🔄 OnRamp Flow (Bank to Wallet)

1. User clicks "Add Money"
2. Frontend sends payment request to a simulated bank API
3. To complete the requested payment, bank API hits a webhook server.
4. Webhook securely updates wallet balance using Express (TypeScript) + Prisma

⚠️ Webhook server ensures idempotent, asynchronous updates under load, preventing frontend inconsistencies

🔐 P2P Transfer Atomicity

To prevent double withdrawal when a user clicks transfer multiple times:

• Used PostgreSQL's FOR UPDATE locking on Balance table for sender row.
• Ensures atomic transactions using prisma.$transaction.

🎨 Jotai State Management

• Global state atoms using Jotai in packages/store
• Active sidebar element tracking for dynamic UI feedback

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🛠️ Tech Stack

Tech	Role
Next.js (TypeScript)	Fullstack frontend/backend
Tailwind CSS	UI styling
Node.js + Express (TypeScript)	Webhook server
PostgreSQL	Database
Prisma ORM	Type-safe DB client
Jotai	Global state management (sidebar)
Turborepo	Monorepo manager
GitHub Actions	Continuous Integration & Delivery
Docker	Containerization
AWS EC2	Cloud deployment

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📂 Folder Structure

paytm-wallet-clone/
├── apps/
│   ├── user-app/           # Next.js (TypeScript) frontend
│   └── webhook-server/     # Express (TypeScript) webhook backend
├── packages/
│   ├── db/                 # Prisma schema + migrations
│   └── store/              # Jotai atoms for global state
├── .github/
│   └── workflows/          # CI/CD GitHub Actions configs
├── docker/                
│   └── Dockerfile.user     # Dockerfile for user app
└── turbo.json              # Turborepo config file

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👨‍💻 Author

Rishu Raj

• 📧 rishuraj1702@gmail.com
• 🐦 @_rishu_raj
• 💻 github.com/1rishuraj

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Ready to deploy and scale. Built for performance, usability, and security.