Mini Chat Application

A simple, professional-grade chat application supporting one-on-one conversations between two users. Built for clarity, maintainability, and ease of testing.

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🚀 Live Demo

View the live demo here

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1. Project Overview

This project is a Mini Chat Application that enables chat between two users. It is designed for demonstration and learning purposes, focusing on clean architecture and modern web technologies.

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2. Tech Stack

Layer	Technology
Frontend	Next.js, Tailwind CSS
Backend	Node.js, Express
Language	TypeScript
Database	MongoDB
Testing	Jest

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3. Getting Started

Prerequisites

• Node.js (v18+ recommended)
• npm
• MongoDB Atlas

1. Clone the repository

git clone <repo-url>
cd Conversations

2. Setup Environment Variables

Backend (backend/.env):

MONGODB_URI=your_mongodb_uri
PORT=4000

Frontend (frontend/.env):

NEXT_PUBLIC_API_BASE=http://localhost:4000

3. Install dependencies & Run (Both Frontend & Backend)

Open two terminals:

Backend

cd backend
npm install
npm run dev

Frontend

cd frontend
npm install
npm run dev

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4. Authentication Simulation

• No real authentication.
• Simulate login by sending an x-user-id header with every API request.
• Seed Users:
  • User 1: { id: 1, name: "Alice" }
  • User 2: { id: 2, name: "Bob" } User 2: { id: 3, name: "Carol" }
• To test chat between users, open two browser windows and set different x-user-id values (e.g., via browser devtools or by modifying the frontend logic).

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5. Implemented Features

• User-to-user chat (1:1)
• Pagination for conversations and messages
• Unit tests for validation
• Clean RESTful API design
• Simple authentication simulation via header

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6. API Endpoints

Method	Endpoint	Description	Auth (x-user-id)
GET	/users/me	Get current user info	Required
GET	/conversations	List conversations (paginated)	Required
POST	/conversations	Start new conversation	Required
GET	/conversations/:id/messages	List messages in conversation	Required
POST	/messages	Send message to conversation	Required

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7. How to Run Tests

Backend (Jest)

cd backend
npm run test

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8. Environment Setup Example

backend/.env

MONGODB_URI= your-url
PORT=4000

frontend/.env

NEXT_PUBLIC_API_BASE=http://localhost:4000

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