Cost Tracker API

A FastAPI-based backend service for managing expenses and tracking costs among friends.

Features

• Expense Management: Create, view, and delete expenses
• Friend Management: Manage a list of friends who share expenses
• Monthly Summaries: Generate monthly expense reports with settlement calculations
• Balance Tracking: Calculate who owes what to whom

Quick Start

Prerequisites

• Python 3.8+
• pip

Installation

1. Clone the repository

2. Install dependencies:

   pip install -r requirements.txt

3. Start the server:

   python -m app.main

   Or use the provided script:

   ./start.sh

The API will be available at http://localhost:8000

Docker Setup

Build and run with Docker:

docker build -t cost-tracker-api .
docker run -p 8000:8000 cost-tracker-api

API Documentation

Once running, visit:

• Interactive API docs: http://localhost:8000/docs
• ReDoc documentation: http://localhost:8000/redoc

Project Structure

expense-tracker-backend/
├── app/
│   ├── api/routes/          # API endpoint definitions
│   ├── core/                # Core configuration and storage
│   ├── models/              # Pydantic data models
│   ├── services/            # Business logic layer
│   └── main.py             # FastAPI application setup
├── data/                   # Data storage (JSON files)
├── tests/                  # Test files
└── requirements.txt        # Python dependencies

API Endpoints

Expenses

• POST /expenses - Create a new expense
• GET /expenses - Get all expenses
• DELETE /expenses/{id} - Delete an expense

Friends

• GET /friends - Get list of friends

Summary

• GET /summary/{year}/{month} - Get monthly expense summary

Configuration

Edit app/core/config.py to configure:

• Friends list
• CORS origins
• Storage settings

Development

Running Tests

python -m pytest tests/

Development Dependencies

pip install -r requirements-dev.txt

Data Storage

The application uses JSON file storage in the data/ directory. Expenses are automatically saved and loaded on startup.