🧾 Employee Payroll System

A Spring Boot REST API that manages employee payroll for both full-time and part-time employees — with a fully Automated AI-Powered Onboarding Pipeline that creates a work email, sends a Slack invite, assigns training modules, configures payroll, and generates a personalized AI welcome message using Groq (LLaMA 3.3) whenever a new employee is hired.

🚀 Tech Stack

🧠 OOP Concepts Demonstrated

📁 Project Structure

src/
└── main/java/com/vikas/
    ├── PayrollApplication.java
    ├── config/
    │   └── SwaggerConfig.java               # Swagger UI configuration
    ├── controller/
    │   └── EmployeeController.java
    ├── service/
    │   ├── EmployeeService.java
    │   ├── OnboardingService.java
    │   ├── AIOnboardingService.java         # AI message via Groq
    │   ├── EmailService.java
    │   ├── SlackService.java
    │   ├── TrainingService.java
    │   └── PayrollSetupService.java
    ├── entity/
    │   ├── Employee.java
    │   ├── FullTimeEmployee.java
    │   └── PartTimeEmployee.java
    ├── repository/
    │   └── EmployeeRepository.java
    ├── dto/
    │   ├── EmployeeRequestDTO.java
    │   ├── EmployeeResponseDTO.java
    │   ├── SalaryResponseDTO.java
    │   └── OnboardingResponseDTO.java
    ├── enums/
    │   └── EmployeeType.java
    └── ExceptionHandler/
        ├── GlobalExceptionHandler.java
        └── OnboardingException.java

⚙️ Setup & Configuration

Prerequisites

• Java 21+
• Maven
• PostgreSQL running locally
• Groq API Key — free at console.groq.com

1. Clone the repository

git clone https://github.com/vikas9013/EmployeePayrollSystem.git
cd EmployeePayrollSystem

2. Create the database

CREATE DATABASE payrolldb;

3. Configure credentials

Copy the example file:

cp src/main/resources/application.properties.example src/main/resources/application.properties

Set these environment variables:

Windows CMD:

set DB_USERNAME=postgres
set DB_PASSWORD=yourpassword
set GROQ_API_KEY=gsk_your_key_here

Mac/Linux:

export DB_USERNAME=postgres
export DB_PASSWORD=yourpassword
export GROQ_API_KEY=gsk_your_key_here

4. Run the application

mvn spring-boot:run

App starts at: http://localhost:8080

📖 Swagger UI — API Documentation

This project includes Swagger UI powered by SpringDoc OpenAPI for interactive API documentation and testing.

How to use Swagger UI

1. Start the application
2. Open http://localhost:8080/swagger-ui.html in your browser
3. Click on any endpoint to expand it
4. Click "Try it out"
5. Fill in the request body or parameters
6. Click "Execute" to test the API live

📡 API Endpoints

📝 Sample Requests

Onboard a Full-Time Employee

POST /api/employees/onboard
{
  "name": "Vikas Singh Rawat",
  "designation": "Software Engineer",
  "type": "FULLTIME",
  "monthlySalary": 85000,
  "hoursWorked": 0,
  "hourlyRate": 0
}

Onboard a Part-Time Employee

POST /api/employees/onboard
{
  "name": "Rahul Mehta",
  "designation": "Intern",
  "type": "PARTTIME",
  "monthlySalary": 0,
  "hoursWorked": 40,
  "hourlyRate": 200
}

Success Response

{
  "employeeId": 1,
  "employeeName": "Vikas Singh Rawat",
  "workEmail": "vikas.singh.rawat@company.com",
  "slackInviteSent": true,
  "trainingAssigned": true,
  "payrollConfigured": true,
  "message": "Onboarding completed successfully for Vikas Singh Rawat",
  "aiOnboardingMessage": "Welcome aboard, Vikas! We are thrilled to have you join our Engineering team."
}

🧪 Testing the API

Using Swagger UI (Recommended)

Open http://localhost:8080/swagger-ui.html and use the Try it out button on any endpoint.

Using curl — Windows CMD

Get all employees:

curl -X GET http://localhost:8080/api/employees

Get employee by ID:

curl -X GET http://localhost:8080/api/employees/1

Get employee salary:

curl -X GET http://localhost:8080/api/employees/1/salary

Onboard Full-Time Employee:

curl -X POST http://localhost:8080/api/employees/onboard -H "Content-Type: application/json" -d "{\"name\": \"Vikas\", \"designation\": \"Software Engineer\", \"type\": \"FULLTIME\", \"monthlySalary\": 85000, \"hoursWorked\": 0, \"hourlyRate\": 0}"

Onboard Part-Time Employee:

curl -X POST http://localhost:8080/api/employees/onboard -H "Content-Type: application/json" -d "{\"name\": \"Rahul\", \"designation\": \"Intern\", \"type\": \"PARTTIME\", \"monthlySalary\": 0, \"hoursWorked\": 40, \"hourlyRate\": 200}"

Update Employee:

curl -X PUT http://localhost:8080/api/employees/1 -H "Content-Type: application/json" -d "{\"name\": \"Vikas Updated\", \"designation\": \"Senior Engineer\", \"type\": \"FULLTIME\", \"monthlySalary\": 95000, \"hoursWorked\": 0, \"hourlyRate\": 0}"

Delete Employee:

curl -X DELETE http://localhost:8080/api/employees/1

Recommended Testing Order

1. POST /onboard → create an employee, note the id in response
2. GET /api/employees → confirm employee is listed
3. GET /api/employees/{id} → fetch by id
4. GET /api/employees/{id}/salary → check salary calculation
5. PUT /api/employees/{id} → update details
6. DELETE /api/employees/{id} → remove employee

🤖 AI-Powered Onboarding Pipeline

When POST /api/employees/onboard is called, 5 steps run automatically:

New Employee Saved to DB
        │
        ▼
1. EmailService           → Creates work email (name@company.com)
        │
        ▼
2. SlackService           → Sends Slack workspace invite
        │
        ▼
3. TrainingService        → Assigns training modules by designation
        │
        ▼
4. PayrollSetupService    → Configures payroll (FULLTIME or PARTTIME)
        │
        ▼
5. AIOnboardingService    → Generates personalized welcome message via Groq AI
        │
        ▼
   OnboardingResponseDTO returned ✅

Training Modules by Designation

🗄️ Database Schema

🔒 Security Notes

• Never commit application.properties with real credentials
• Always use environment variables for secrets
• application.properties is listed in .gitignore
• Use application.properties.example as a safe template

👨‍💻 Author

Vikas Singh Rawat
GitHub · LinkedIn