🔍 Identity Reconciliation Backend

This backend service helps intelligently reconcile user identities (email & phone number) to identify whether multiple contact records belong to the same person.

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🚀 Features

• Match users by email, phone number, or both
• Automatically merges multiple identities
• Handles complex overlap scenarios (merge logic)
• Returns consolidated contact info
• Organized in clean architecture: routes, controllers, services, models

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🧠 Use Case

Suppose a user (like "Doc") uses different emails and phone numbers while placing orders. This service ensures all those contacts are reconciled and linked to a single primary identity.

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🧰 Tech Stack

Layer	Tech Used
Language	Node.js (ES Modules)
Framework	Express
ORM	Prisma
Database	PostgreSQL
Dev Tools	Nodemon, dotenv
API Testing	Postman
Folder Design	MVC-style architecture

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📁 Folder Structure

identity-reconciliation-backend/
├── prisma/                 # Prisma schema and DB migrations
├── src/
│   ├── controllers/        # Route handlers
│   ├── routes/             # Express route definitions
│   ├── services/           # Core logic (merge & insert)
│   ├── models/             # Prisma client config
│   └── index.js            # Entry point
├── .env                    # Environment variables (not committed)
├── .gitignore
├── package.json
└── README.md

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⚙️ Setup Instructions

✅ Prerequisites

• Node.js installed
• PostgreSQL installed
• pgAdmin (optional GUI for DB)
• GitHub account

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🧪 Step-by-Step Setup

1️⃣ Clone the Repository

git clone https://github.com/bharani-coder-27/Identity-Reconciliation-Backend
cd identity-reconciliation-backend

2️⃣ Install Dependencies

npm install

3️⃣ Configure .env

Create a file named .env in the root directory:

DATABASE_URL="postgresql://<username>:<password>@localhost:5432/<your_database>"
PORT=3000

Replace <username>, <password>, and <your_database> with your PostgreSQL credentials.

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4️⃣ Run Database Migration

This will create the Contact table in your DB:

npx prisma migrate dev --name init

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5️⃣ Start the Server

npm run dev

📍 Server will run at: http://localhost:3000

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📮 API Endpoint

🔹 POST /identify

✅ Request Example

{
  "email": "doc@example.com",
  "phoneNumber": "1234567890"
}

🔁 Response Example

{
  "primaryContactId": 1,
  "emails": ["doc@example.com", "doc@x.com"],
  "phoneNumbers": ["1234567890", "9876543210"],
  "secondaryContactIds": [2, 3]
}
```

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## 🧪 Testing the API

You can test the API using:

- [Postman](https://www.postman.com/)
- [Thunder Client](https://www.thunderclient.com/) (VS Code extension)

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## ✅ Bonus Tips

- Use `npx prisma studio` to open Prisma GUI and manage data.
- Use seed scripts to insert test cases.
- Add more endpoints like `/contacts`, `/delete`, etc. for admin access.

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## ✍️ Author

**Bharanidharan G**  
[GitHub](https://github.com/bharani-coder-27)

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## 📄 License

This project is open-source under the MIT License.


## 🔖 Tags

`Node.js` `Express` `Prisma` `PostgreSQL` `Backend API` `Identity Resolution` `REST API`