TradeUp - Realtime Chat-based Marketplace

TradeUp is a real-time chat-based web application that allows users to post items for sale and negotiate deals via direct messaging. Inspired by platforms like OLX, it integrates chat functionality with marketplace listings, focusing on simplicity and user engagement.

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🚀 Features

• ✅ User Authentication (Register/Login with JWT-based sessions)
• ✅ Post Items for Sale with image, price, and start chat option
• ✅ Chat Functionality (Start conversations, real-time messaging)
• ✅ Chat Sidebar showing active conversations
• ✅ Responsive and Minimal UI (basic responsive behavior)
• ✅ Secure JWT Handling and protected routes
• ✅ PostgreSQL for relational data storage
• ✅ Socket.io for real-time chat functionality
• ✅ Session persistence and error handling (like auto-redirect on expired JWT)
• ✅ Dynamic feed to browse all available items

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🛠️ Tech Stack

Technology	Purpose
Node.js	Backend runtime
Express.js	Web framework
EJS	Server-side rendering
PostgreSQL	Relational database
Socket.io	Real-time messaging
JWT (jsonwebtoken)	Authentication and session management
Render	Deployment platform
CSS (Custom)	Styling (basic responsiveness)

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📸 Screenshots

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🧑‍💻 How to Use

1. Register/Login to create an account.
2. Post a new item for sale via your profile.
3. Browse other users' listings on the feed.
4. Start a chat with sellers/buyers to negotiate.
5. View ongoing chats in the sidebar (on the chats screen) and chat in real-time.

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⚙️ Setup Locally

Prerequisites:

• Node.js and npm
• PostgreSQL installed and running

1. Clone the repo

npm install

2. Install dependencies

git clone https://github.com/yourusername/tradeup.git

3. Setup PostgreSQL Database

• Create a new PostgreSQL database.
• Run schema setup (create users, items, chats, messages tables).
• Update .env

DB_USER="dbuser"
DB_HOST="dbhost"
DB_NAME="dbname"
DB_PASS="dbpass"
DB_PORT=5432
JWT_SECRET="yousecret"
NODE_ENV="development"
PORT=3000

4. Run the app

node app

Go to http://localhost:3000 in your browser.

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🌐 Deployment

• App is deployed on Render.
• Environment variables are managed via Render Dashboard.
• SSL/TLS handled automatically in production with PostgreSQL and backend setup.

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🔒 Security

• JWT authentication to secure user sessions.
• Input validation to prevent SQL injections and malformed data.
• Secure WebSocket connection for real-time chats.

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✅ Future Improvements

• ⚙️ Option to edit posts
• 📱 Mobile responsive design.
• 📸 Add image upload for items.
• 🔔 Real-time notifications for new messages and chat requests.
• ❤️ Wishlist/Save Items.
• 🔍 Search and filter functionality.
• ✨ Improve chat UX with typing indicators and message status.

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💡 Learning Takeaways

• End-to-end authentication system with JWT & cookies.
• Real-time WebSocket communication with Socket.io.
• Handling production-specific configurations like SSL for PostgreSQL.
• Database schema design for marketplace and chat apps.
• Frontend and backend integration using EJS and REST API.

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🔗 Live Demo

TradeUp