NSE Live Data Proxy

A lightweight Vercel-deployed proxy server and web UI for fetching live data from the National Stock Exchange of India (NSE) API. Bypasses browser CORS restrictions by routing requests through a serverless backend.

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Features

• CORS Proxy -- Routes requests to NSE India's API through a Vercel serverless function, avoiding browser-side CORS blocks
• Cookie Management -- Performs a warm-up request to nseindia.com to obtain session cookies before making the actual API call
• Live Web UI -- Clean, dark-themed frontend to input any NSE API path and view formatted JSON responses
• Configurable Endpoints -- Change the API path dynamically from the UI to test any NSE endpoint
• Response Caching -- Short-lived Cache-Control headers (s-maxage=10) reduce redundant requests and lower the chance of IP blocks
• Zero Dependencies -- Pure Node.js serverless function with no third-party packages

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Project Structure

testtest/
├── api/
│   └── nse.js              # Vercel serverless function (CORS proxy to NSE API)
├── index.html              # Frontend UI for querying NSE data
├── Late_Night_PYQ_Marathons.min.html.gz   # Compressed archived HTML asset
├── package.json            # Project metadata
├── .gitignore              # Git ignore rules
├── LICENSE                 # MIT License
└── README.md               # Project documentation

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Prerequisites

• Node.js 18 or later
• A Vercel account (for deployment)
• Vercel CLI (optional, for local development)

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Installation

1. Clone the repository

   git clone https://github.com/tushar-alt/testtest.git
   cd testtest

2. Install Vercel CLI (optional, for local dev)

   npm install -g vercel

3. Link to your Vercel project (optional)

   vercel link

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Usage

Local Development

vercel dev

This starts a local development server. Open http://localhost:3000 in your browser.

Deployment

vercel --prod

Deploys the application to Vercel production.

Using the Web UI

1. Open the deployed URL or localhost:3000
2. The default path is pre-filled with NextApi/apiClient?functionName=getIndexData&type=All (fetches all index data)
3. Click Fetch to retrieve and display the JSON response
4. Modify the path input to query other NSE API endpoints

API Endpoint

The proxy function is available at:

GET /api/nse?path=<nse-api-path>

Parameters:

Param	Type	Required	Description
path	string	Yes	The NSE API path (without the base URL prefix)

Example:

GET /api/nse?path=NextApi/apiClient?functionName=getIndexData&type=All

Response: Proxied JSON from NSE India, with Access-Control-Allow-Origin: * header.

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How It Works

Browser  -->  /api/nse?path=...  -->  Vercel Serverless Function
                                          |
                                          |--> warm-up GET nseindia.com (grab cookies)
                                          |--> GET nseindia.com/api/<path> (with cookies)
                                          |
                                     JSON response --> Browser

1. The browser sends a request to /api/nse with the desired NSE path
2. The Vercel serverless function (api/nse.js) first hits https://www.nseindia.com/ to obtain session cookies
3. It then forwards the actual API request to https://www.nseindia.com/api/<path> with the cookies attached
4. The response is sent back to the browser with permissive CORS headers

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Tech Stack

Layer	Technology
Frontend	Vanilla HTML/CSS/JS
Backend	Vercel Serverless Functions (Node.js)
Deployment	Vercel
API Source	NSE India (nseindia.com)

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License

This project is licensed under the MIT License. See the LICENSE file for details.

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Author

tushar-alt -- 2026