📈 Live Stock Price Tracker (SSE)

This is a simple web application that shows live stock prices using Server-Sent Events (SSE) and real-time stock data fetched from external APIs (e.g., Twelve Data or Finnhub).

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🚀 Features

• Real-time stock price updates (e.g., Apple Inc)
• Uses SSE (Server-Sent Events) for pushing data from backend to frontend
• Built using Node.js, Express, Axios, and vanilla HTML/CSS/JS
• API data source can be switched easily (e.g., from Twelve Data to Finnhub)
• Minimal, easy-to-understand project for learning SSE & real-time data fetching

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🛠 Tech Stack

• Frontend: HTML, JavaScript
• Backend: Node.js, Express
• API: Twelve Data API

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📂 Project Structure

├── server.js # Express server (SSE + API fetch) ├── .env # API keys and port config ├── public/ │ └── index.html # Frontend HTML for displaying live prices └── README.md

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⚙️ Setup Instructions

1. Clone the repository

bash git clone https://github.com/your-username/stock-price-sse.git cd stock-price-sse

2. Install dependencies

bash npm install

3. Set up .env file

Create a .env file at the root with the following content:

env API_KEY=your_api_key_here PORT=5000

🔑 You can get a free API key from:

• Twelve Data

4. Start the backend server

bash node server.js

5. Open frontend

Use Live Server (VS Code extension) or any static file server to open index.html:

Then open http://localhost:5500 in your browser.

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🧪 Testing SSE

If the real API doesn't provide frequent updates (e.g., free tier of Twelve Data), you can test with random mock data instead:

js const price = (150 + Math.random() * 10).toFixed(2); res.write(`data: ${JSON.stringify({ symbol: 'AAPL', price })}

`);

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🔐 CORS Note

If you see a CORS error, make sure:

• The backend uses correct cors() settings.
• The frontend and backend run on the same origin (use localhost consistently).
• Example: js app.use(cors({ origin: 'http://localhost:5500', credentials: true }));

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📌 Use Cases

• Learning and demoing Server-Sent Events
• Building simple dashboards
• Real-time data stream visualization

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🤝 Contributing

Contributions are welcome! Feel free to fork the repo and submit a PR.

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📜 License

MIT License. See LICENSE file for details.