FastAPI Backend

FastAPI backend service with SQLAlchemy 2.0 ORM, PostgreSQL, and Alembic migrations.

Tech Stack

• FastAPI
• SQLAlchemy 2.0 (Mapped[], mapped_column, DeclarativeBase)
• PostgreSQL (psycopg2-binary)
• Alembic (schema migrations + seed migration)
• Pydantic Settings (.env based config)

Project Structure

fastapi-be/
├── app/
│   ├── main.py
│   ├── core/
│   │   ├── config.py
│   │   └── database.py
│   ├── routes/
│   │   └── health.py
│   ├── controllers/
│   ├── services/
│   ├── models/
│   └── schemas/
|
├── .env
├── Dockerfile
├── docker-compose.yml
├── requirements.txt
└── README.md

Environment Configuration

The project reads settings from .env via app/core/config.py.

Required variables:

APP_NAME
APP_VERSION
DATABASE_URL

Common Commands

# create a new migration from model changes
alembic revision --autogenerate -m "describe changes"

# apply all migrations
alembic upgrade head

# rollback one revision
alembic downgrade -1

# show current revision
alembic current

# show migration history
alembic history

Local Development

1) Start PostgreSQL (Docker)

docker compose up -d

2) Create virtual environment and install dependencies

python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt

3) Run migrations

alembic upgrade head

4) Start Server

uvicorn app.main:app --reload