Expense Management System

A simple expense tracking system with a Streamlit frontend and a FastAPI backend, backed by a MySQL database. It lets you log daily expenses by category, edit/replace a day's entries, and view a percentage breakdown of spending by category over a date range.

Features

• Add/Update tab — enter up to 5 expenses (amount, category, notes) for a given date. Submitting replaces all existing entries for that date.
• Analytics tab — pick a start/end date range and get a bar chart plus table showing total spend and percentage share per category.
• Categories: Rent, Food, Shopping, Entertainment, Other.
• Backend logs every DB operation (fetch/insert/delete) to backend/server.log.

Screenshots

Add/Update tab — enter expenses for a date, grouped by amount, category, and notes:

Analytics tab — category breakdown as a bar chart with an underlying data table:

Project Structure

• frontend/: Streamlit application code.
  • app.py — entry point, wires up the Add/Update and Analytics tabs.
  • add_update_ui.py — Add/Update tab (calls GET/POST /expenses/{date}).
  • analytics_ui.py — Analytics tab (calls POST /analytics/).
• backend/: FastAPI backend server code.
  • server.py — API routes.
  • db_helper.py — MySQL queries (connects to localhost:3306, db expense_manager).
  • logging_setup.py — file logger used by db_helper.py.
• tests/: Test cases for the backend.
• requirements.txt: Required Python packages.
• README.md: This file.

API Endpoints (backend/server.py)

Method	Path	Description
GET	/expenses/{date}	Returns all expenses for the given date (YYYY-MM-DD).
POST	/expenses/{date}	Replaces all expenses for the given date with the provided list.
POST	/analytics/	Body: {"start_date", "end_date"}. Returns per-category total and percentage of spend in that range.

Interactive API docs are available at http://127.0.0.1:8000/docs once the backend is running.

Setup Instructions

1. Clone the repository:

   git clone https://github.com/yourusername/Expense-Tracking-System.git
   cd Expense-Tracking-System

2. Install dependencies:

   pip install -r requirements.txt

3. Set up MySQL: create a database named expense_manager with an expenses table:

   CREATE TABLE expenses (
       id INT AUTO_INCREMENT PRIMARY KEY,
       expense_date DATE NOT NULL,
       amount DECIMAL(10, 2) NOT NULL,
       category VARCHAR(255) NOT NULL,
       notes VARCHAR(255)
   );

   db_helper.py connects with host="localhost", user="root", password="root" — update these if your local MySQL setup differs.
4. Run the FastAPI server (from the backend/ directory, since it imports db_helper directly):

   cd backend
   uvicorn server:app --reload

5. Run the Streamlit app (from the project root):

   streamlit run frontend/app.py

Running Tests

pytest

Tests in tests/backend/test_db_helper.py expect specific rows to already exist in the database (e.g. an expense on 2026-07-11), so they're meant to run against a seeded/known dataset rather than an empty one.