Reminder App

Reminder App

A reminder application with email notifications. Built to explore FastAPI and learn how to integrate background task processing with Celery.

Why this stack?

I wanted to get hands-on with FastAPI and see how it handles operations using endpoints and background tasks. Since FastAPI doesn't use templates like Django or Flask, I paired it with React for the frontend — this kept the backend focused purely on API logic.

The project taught me:

• How to structure FastAPI application
• Working with Celery for scheduled tasks
• Managing timezones properly (UTC in backend, local time in frontend)
• Creating basic frontend using React

Features

• Create reminders with title, description, deadline and email
• Choose when to get notified:
  • 15 minutes before
  • 1 hour before
  • 1 day before
• Automatic email notifications via Celery Beat:
  • Tasks are checked/sent every minute by default (can be edited in backend/app/config/celery_app.py)
• All times stored in UTC, displayed in local timezone

Tech Stack

Backend

• FastAPI
• SQLAlchemy (SQLite)
• Celery + Redis
• Pydantic for validation
• Pytest

Frontend

• React

Infrastructure

• Docker

Testing & Quality Assurance

To ensure the reliability of the API and database operations the project includes a comprehensive test suite:

• Integrations Tests: Built with Pytest, covering the full CRUD lifecycle
• API Simulation: Uses FastAPI's TestClient with httpx to simulate real-world requests
• Isolated Database: Tests run on separate, temporary SQLite database to ensure no side effects on development base
• CI/CD Pipeline: Automated testing via GitHub Actions. Every push and pull request triggers the test suite on clean Linux environment.

Note on Celery Testing: Background workers and email tasks are currently excluded from the integration suite to keep the CI pipeline lightweight. These components are verified through manual end-to-end testing with a Redis broker.

To run tests locally:

```
cd backend
pytest --cov=app --cov-report=term-missing
```

Quick Start

1. Clone the repository

   git clone
   cd Reminder
   

2. Set up environment variables

   Create .env file in the root directory

   MAIL_HOST=smtp.gmail.com
   MAIL_USERNAME=your_email@gmail.com
   MAIL_PASSWORD=your_app_password
   MAIL_PORT=587
   

   Note: Password should be app password, not the one you use to log in to Gmail.

   https://support.google.com/mail/answer/185833?hl=en#zippy=

3. Run FastAPI to create database:

   cd backend/app
   fastapi dev main.py
   

   After seeing "test.db" in db/ press CTRL + C to close the server.

4. Run with Docker

   docker compose up --build
   

The app will be available at: - Frontend: http://localhost:5173 - Backend API: http://localhost:8000 - API Docs: http://localhost:8000/docs

Project Structure

├── .github/workflows/
│   └── tests.yml           # Config file for GitHub Actions
│
├── backend/
│   ├── app/
│   │   ├── config/
│   │   ├── main.py         # FastAPI routes
│   │   ├── schemas.py      # Pydantic models
│   │   ├── send_mail.py    # Email logic
│   │   └── tasks.py        # Celery tasks
│   │ 
│   ├── db/
│   │   ├── models.py       # SQLAlchemy models
│   │   ├── crud.py         # Database operations
│   │   └── base.py         # DB connection
│   │  
│   ├── tests/
│   │   ├── conftest.py     # Config file with fixtures
│   │   └── test_api.py     # File with tests
│   │ 
│   ├── Dockerfile
│   ├── requirements.txt
│   └── pytest.ini          # Config file for pytest
│ 
├── frontend/
│   ├── src/
│   │   ├── components/     # React components
│   │   ├── App.jsx
│   │   └── main.jsx
│   ├── package.json
│   └── vite.config.js
│
├── docker-compose.yml
├── .env
└── README.md

What I learned?

• FastAPI makes building API surprisingly straightforward
• Celery Beat is perfect for recurring tasks, but need careful timezone handling for tasks connected with time
• Docker is great for managing multiple services, especially when each one of them needs command to start in different terminal
• SQLite is fine for development, but production may need PostgreSQL
• Creating basic layout with React and its structure

Future Improvements

Things I'd add if I continue this project:

• User authentication (not all reminders visible for everyone)
• PostgreSQL instead of SQLite (for more workers and remote database)
• Sending alerts on mobile phone
• Better error handling and validation
• Deployment setup

License

MIT

---

Feel free to use this as a reference or starting point for your own projects.