💳 Paytm - Full-Stack Digital Wallet

This project is a full-stack clone of the Paytm digital wallet, built with a modern, scalable, and type-safe stack. It features a complete monorepo architecture using Turborepo to manage separate applications for users, merchants, and backend services.

The primary user-app allows users to manage their wallet, send money to other users (P2P), and add funds from their bank via a simulated bank onramp. The entire system is built for reliability, using PostgreSQL and Prisma to ensure database integrity and ACID properties for all financial transactions.

✨ Live Demo (User App)

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📸 Screenshots

Landing Page	Dashboard Overview
	!

(To add these: create a docs folder in your project root, add your screenshots, and commit them.)

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🚀 Core Features

• User Authentication: Secure sign-up and sign-in using NextAuth.
• P2P (Peer-to-Peer) Transfers: Instantly send money to other users on the platform.
• Wallet Management: A personal digital wallet to hold and manage funds.
• Add Money: Simulate adding money to the wallet via a bank onramp.
• Transaction History: A complete, filterable list of all P2P and onramp transactions.
• Decoupled Architecture: Built as a monorepo with separate frontends and backend services.
• Asynchronous Webhooks: A dedicated bank-webhook service to process bank transfers asynchronously.

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🛠️ Architecture & Tech Stack

This project uses a Turborepo monorepo to manage multiple applications and shared packages.

Core Technologies

• Monorepo: Turborepo
• Framework: Next.js (React)
• Backend: Node.js (for bank-webhook service)
• Database: PostgreSQL
• ORM: Prisma
• Authentication: NextAuth.js
• Styling: Tailwind CSS
• Language: TypeScript
• Deployment: Docker, Vercel/Netlify

Project Structure

merchant-paytm/
├── apps/
│   ├── bank-webhook/  # Node.js service for bank webhooks
│   ├── merchant-app/  # Next.js app for merchants
│   └── user-app/      # Main Next.js app for users
├── packages/
│   ├── db/            # Shared Prisma schema and database client
│   └── ui/            # Shared React component library
├── .gitignore
├── package.json
└── turbo.json         # Turborepo configuration

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💡 Principles Implemented

• ACID Properties: All P2P transfers are executed inside a prisma.$transaction. This ensures that debiting the sender and crediting the receiver is an atomic operation: it either fully completes or fails entirely, preventing data inconsistency.
• Separation of Concerns: By splitting the app into a user-app, merchant-app, and a bank-webhook service, we create a more resilient and scalable system. The bank-webhook can process payments independently without blocking the user-facing application.

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🏁 Getting Started (Local Development)

Prerequisites

• Node.js (v18+)
• npm (or npm/yarn)
• Docker (for running PostgreSQL)

1. Clone the repository

git clone https://github.com/KartikeyNamdev/Merchant-Paytm
cd merchant-paytm

2. Install dependencies

npm install

3. Set up the Database (Docker)

1. Run the PostgreSQL database using Docker:

docker run --name paytm-db -e POSTGRES_PASSWORD=mysecretpassword -p 5432:5432 -d postgres

2. Create a .env file in the root of the project (or in apps/user-app).

You must do this, or Prisma will fail.

# .env
DATABASE_URL="postgresql://postgres:mysecretpassword@localhost:5432/postgres"

# For NextAuth
NEXTAUTH_URL="http://localhost:3001"
NEXTAUTH_SECRET="somesecretstring"

4. Run Database Migrations

Push the Prisma schema to your new database.

npm db:push # Assuming you have a script `prisma db push`

5. Run the Project

This will start all applications in the monorepo.

npm dev

Your user-app will be available at http://localhost:3001.

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📝 License

This project is open source and available under the MIT License.

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🤝 Contributing

Contributions, issues, and feature requests are welcome! Feel free to check the issues page.

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👨‍💻 Author

Your Name

• GitHub: @KartikeyNamdev
• LinkedIn: Your Name

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