💼 Expense Approval System

📌 Overview

Companies often struggle with manual expense reimbursement processes that are time-consuming, error-prone, and lack transparency.
This project is a smart Expense Management & Approval System that allows employees to submit expenses and managers/admins to approve them through multi-level workflows with conditional rules.

Built in 1 day hackathon (virtual round).

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🎯 Core Features

• Authentication & Role Management

  • Roles: Admin, Manager, Employee
  • Admin can create employees/managers and assign roles

• Expense Submission (Employee)

  • Submit expense claims (amount, category, description, date, receipt upload)
  • Multi-currency support (converted to company’s default currency)
  • View personal expense history (approved/rejected)

• Approval Workflow (Manager/Admin)

  • Sequential approvals: Manager → Finance → Director
  • Conditional rules:
    • ✅ Percentage rule (e.g., 60% approvals = approved)
    • ✅ Specific approver rule (e.g., CFO auto-approves)
    • ✅ Hybrid rule (e.g., 60% OR CFO approval)

• Extra Features

  • OCR Receipt Scanning (auto-extract amount/date/vendor)
  • Real-time currency conversion using Exchangerate API

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🏗️ Tech Stack

Frontend

• React + TailwindCSS

Backend

• FastAPI (Python) / Express (Node.js)
• REST APIs for auth, expense submission, approval workflow

Database

• SQLite (for hackathon speed, easy to switch to PostgreSQL)

APIs

• Country & Currency: REST Countries
• Currency Conversion: Exchangerate API

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📂 Project Structure

expense-approval-system/ │ ├── backend/ # API + workflow engine │ ├── app/ │ │ ├── main.py │ │ ├── models.py │ │ ├── schemas.py │ │ ├── routes/ │ │ └── services/ │ └── requirements.txt │ ├── frontend/ # React + Tailwind │ ├── src/ │ │ ├── components/ │ │ └── pages/ │ └── package.json │ ├── docs/ # Hackathon docs │ ├── architecture.png │ └── demo-script.md │ ├── README.md └── docker-compose.yml