Leave FLow

A web application where employees can apply for leave and the employers can either approve or reject the requests.

Tech Stack: Vue.js + Tailwind CSS (Frontend), Node.js + Express (Backend), MongoDB Atlas (Database)

Live URL: http://16.16.186.125/

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Features

Employee

• Sign up / Log in
• Apply for leave (type, start date, end date, reason)
• View all own leave requests with status (Pending / Approved / Rejected)
• Overlap detection — cannot apply for duplicate date ranges
• Dashboard stats (total, pending, approved, rejected)

Employer

• Sign up / Log in
• View all employee leave requests (with filter by status)
• Approve or Reject requests with an optional review note
• Dashboard stats overview

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Project Setup

1. MongoDB Atlas

1. Go to cloud.mongodb.com and create a free account
2. Create a cluster -> M0 Free Tier
3. Create a database user with a username and password
4. Network Access → Add IP Address → enter 0.0.0.0/0
5. Connect → Drivers → copy the connection string

2. AWS EC2

1. Go to aws.amazon.com
2. Go to EC2 and Launch Instance
   • AMI: Ubuntu 24.04 LTS
   • Instance type: t3.micro
   • Key pair: Create new → download .pem file
   • Firewall: enable HTTP
3. Once running → connect to EC2 instance

Step 3 — Install requirements onto EC2

sudo apt update
curl -fsSL https://deb.nodesource.com/setup_20.x | sudo -E bash -
sudo apt-get install -y nodejs nginx unzip
sudo npm install -g pm2

Step 4 — Upload and run the code

• Upload the project zip file to EC2 and then unzip it
• backend folder -> create a .env file for environment variables with MongoDB URI and JWT secret.
• Run npm install and start with PM2.
• frontend folder -> run npm install and npm run build.
• Configure Nginx to serve the frontend and proxy API requests to the backend.
• Access the app at http://16.16.186.125/

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API Endpoints

Auth

Method	Endpoint	Description
POST	/api/auth/register	Register as employee or employer
POST	/api/auth/login	Login and receive JWT token
GET	/api/auth/me	Get current logged in user

Leaves

Method	Endpoint	Role	Description
POST	/api/leaves	Employee	Apply for leave
GET	/api/leaves/my	Employee	View own leave requests
GET	/api/leaves	Employer	View all leave requests
PATCH	/api/leaves/:id/review	Employer	Approve or reject a leave
GET	/api/leaves/stats	Employer	Get counts by status

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Deployment Topology

User's Browser
      ↓
AWS EC2 (Ubuntu 24.04, t3.micro)
      ├── Nginx (port 80)
      │     ├── /* → Vue.js frontend
      │     └── /api/* → Node.js backend (port 5000)
      └── Node.js + Express (managed by PM2)
            ↓
      MongoDB Atlas