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Crypto Tracker Api

This repository contains the implementation of the backend assignment for the KoinX Backend Internship. The project is designed using Node.js and MongoDB, and it follows modular structure.

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Table of Contents

• Features
• Technology Stack
• Folder Structure
• Getting Started
  • Prerequisites
  • Setup
• API Documentation

Features

1. Background Job:

   • Fetches cryptocurrency data for Bitcoin, Ethereum, and Matic every 2 hours.
   • Data includes the current price in USD, market cap in USD, and 24-hour change.
   • Uses the CoinGecko API for fetching cryptocurrency data.

2. APIs:

   • /stats: Retrieves the latest data for a specific cryptocurrency.
   • /deviation: Calculates the standard deviation of the last 100 prices for a cryptocurrency.

3. Database:

   • Stores cryptocurrency data in MongoDB Atlas.

4. Deployment:

   • Hosted on AWS Elastic Beanstalk.
   • Public URL: Crypto API Environment

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Technology Stack

• Backend: Node.js, Express.js
• Database: MongoDB
• Scheduler: node-cron
• HTTP Client: Axios

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Folder Structure

project-root/
├── src/
│   ├── jobs/                    # Background jobs
│   │   └── fetchCryptoData.js   # Cryptocurrency data fetching job
│   │
│   ├── controllers/             # Request handlers
│   │   ├── statsController.js   # Cryptocurrency stats controller
│   │   └── deviationController.js # Price deviation controller
│   │
│   ├── models/                  # Database models
│   │   └── Crypto.js     # Cryptocurrency price record schema
│   │
│   ├── routes/                  # API routes
│   │   ├── stats.js      # Stats endpoint routes
│   │   └── deviation.js  # Deviation endpoint routes
│   │
│   ├── utils/                   # Utility functions
│   │   └── calculateDeviation.js      # Standard deviation calculator
│   │
│   └── config/                 # Configuration files
│       └── db.js              # Database configuration
│
├── .env                     # Environment variables
├── .gitignore              # Git ignore rules
├── server.js                  # Express Application (server)
├── package.json            # Project dependencies and scripts
├── package-lock.json       # Locked dependencies
├── eslint.config.mjs       # Lint config to enforce coding standards
└── README.md              # Project documentation

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Getting Started

Prerequisites

• Node.js (v22 or higher)
• MongoDB (local or hosted on MongoDB Atlas)

Setup

1. Clone the Repository:

   git clone https://github.com/your-username/koinx-backend-assignment.git
   cd koinx-backend-assignment
   
   

2. Install Dependencies:

   npm install
   

3. Configure Environment Variables: Create a .env file in the root directory and add the following:

   MONGO_URI=<your-mongodb-connection-string>
   PORT=3000
   

4. Start the Application: bash

   npm start
   

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API Documentation

1. /stats (GET)

• Description: Fetches the latest stats for a specific cryptocurrency.
• Query Parameters:
  • coin (required): One of bitcoin, ethereum, or matic-network.

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2. /deviation (GET)

• Description: Calculates the standard deviation of the last 100 prices for a cryptocurrency.
• Query Parameters:
  • coin (required): One of bitcoin, ethereum, or matic-network.

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Testing

API Endpoints

1. Get Cryptocurrency Statistics

Retrieves the latest price, market cap, and 24-hour change for a specific cryptocurrency.

Endpoint: /api/stats
Method: GET
Query Parameters:

• coin: The cryptocurrency ID (bitcoin, ethereum, or matic-network)

Example Request:

curl "http://crypto-api-env.eba-2xu2tz2m.ap-south-1.elasticbeanstalk.com/api/stats?coin=bitcoin"

Sample Response:

{
    "price": 42956.78,
    "marketCap": 842956834521,
    "24hChange": -1.23
}

2. Get Price Standard Deviation

Calculates the standard deviation of prices from the last 100 records for a specific cryptocurrency.

Endpoint: /api/deviation
Method: GET
Query Parameters:

• coin: The cryptocurrency ID (bitcoin, ethereum, or matic-network)

Example Request:

curl "http://crypto-api-env.eba-2xu2tz2m.ap-south-1.elasticbeanstalk.com/api/deviation?coin=bitcoin"

Sample Response:

{
    "deviation": 1234.56
}

Testing Tools

• Postman: Recommended for API testing and exploration
• cURL: Command-line tool for making HTTP requests

Base URL

All API requests should be made to:

http://crypto-api-env.eba-2xu2tz2m.ap-south-1.elasticbeanstalk.com

Error Responses

In case of errors, the API will return appropriate HTTP status codes along with error messages:

{
    "error": "Invalid cryptocurrency specified",
    "status": 400
}

Common status codes:

• 200: Successful request
• 400: Bad request (e.g., invalid parameters)
• 404: Resource not found
• 500: Internal server error