fastapi-auth-starter 0.1.5

A clean architecture FastAPI starter template with authentication, PostgreSQL, and Alembic migrations

FastAPI Auth Starter

A clean architecture FastAPI project starter with PostgreSQL and Alembic migrations.

Project Structure

fastapi_auth_starter/
├── app/
│   ├── __init__.py
│   ├── main.py              # FastAPI application entry point
│   ├── api/
│   │   └── v1/
│   │       ├── api.py       # API router aggregation
│   │       └── routes/
│   │           └── health.py  # Health check endpoint
│   ├── core/
│   │   ├── config.py        # Application configuration
│   │   └── database.py      # Database connection and session management
│   ├── models/              # SQLAlchemy database models
│   ├── services/            # Business logic services
│   └── db/                  # Database utilities
├── alembic/                 # Database migration scripts
├── alembic.ini              # Alembic configuration
├── pyproject.toml           # Project dependencies (uv)
└── README.md

Features

• ✅ Clean architecture with separation of concerns
• ✅ FastAPI with async SQLAlchemy
• ✅ PostgreSQL database support
• ✅ Alembic for database migrations
• ✅ Health check endpoint
• ✅ Dependency injection with FastAPI
• ✅ Environment-based configuration

Prerequisites

• Python 3.12+ (3.13 for local dev, 3.12 for Vercel deployment)
• uv package manager
• PostgreSQL database (local or remote)

Setup

1. Install Dependencies

Dependencies are managed with uv. They are automatically installed when you run commands with uv run.

2. Configure Environment Variables

Important: Copy the example environment file and configure your settings:

cp .env.example .env

Then edit .env with your configuration:

# Database Configuration
DATABASE_URL=postgresql+asyncpg://user:password@localhost:5432/fastapi_auth

# API Configuration (optional - defaults are fine)
API_V1_PREFIX=/api/v1
PROJECT_NAME=FastAPI Auth Starter
VERSION=0.1.0

Note:

• The .env file is gitignored and should not be committed
• The application uses asyncpg for async operations, but Alembic uses psycopg2 for migrations (sync driver)
• All sensitive configuration should be in .env file, not hardcoded

3. Initialize Database

First, ensure PostgreSQL is running and create the database:

createdb fastapi_auth

Or using PostgreSQL client:

CREATE DATABASE fastapi_auth;

4. Run Migrations

# Create initial migration (if needed)
uv run alembic revision --autogenerate -m "Initial migration"

# Apply migrations
uv run alembic upgrade head

Running the Application

Development Server

uv run uvicorn app.main:app --reload

The API will be available at:

• API: http://localhost:8000
• Docs: http://localhost:8000/docs
• ReDoc: http://localhost:8000/redoc

Health Check

Test the health endpoint:

curl http://localhost:8000/api/v1/health

Expected response:

{
  "status": "healthy",
  "message": "Service is running"
}

Development

Adding New Routes

1. Create a new route file in app/api/v1/routes/
2. Import and include the router in app/api/v1/api.py

Example:

# app/api/v1/routes/users.py
from fastapi import APIRouter

router = APIRouter(prefix="/users", tags=["users"])

@router.get("/")
async def get_users():
    return {"users": []}

Then add to app/api/v1/api.py:

from app.api.v1.routes import users
api_router.include_router(users.router)

Adding Database Models

1. Create model in app/models/
2. Import in app/models/__init__.py
3. Import in alembic/env.py (for autogenerate)

Example:

# app/models/user.py
from sqlalchemy import Column, Integer, String
from app.core.database import Base

class User(Base):
    __tablename__ = "users"
    
    id = Column(Integer, primary_key=True)
    email = Column(String, unique=True, index=True)

Creating Migrations

# Auto-generate migration from model changes
uv run alembic revision --autogenerate -m "Description of changes"

# Create empty migration
uv run alembic revision -m "Description of changes"

Applying Migrations

# Apply all pending migrations
uv run alembic upgrade head

# Rollback one migration
uv run alembic downgrade -1

# Rollback to specific revision
uv run alembic downgrade <revision>

Architecture

Layers

• API Layer (app/api/): Route handlers, request/response models
• Service Layer (app/services/): Business logic, domain operations
• Model Layer (app/models/): SQLAlchemy database models
• Core Layer (app/core/): Configuration, database setup, utilities

Dependency Injection

FastAPI's dependency injection is used throughout:

• Database sessions via get_db() dependency
• Configuration via settings object
• Custom dependencies in app/core/dependencies.py (create as needed)

Deployment

Vercel Deployment

1. Install Dev Dependencies Locally:

   uv sync  # Installs all dependencies including dev
   

2. Set Environment Variables in Vercel:

   • Go to your project settings in Vercel
   • Add DATABASE_URL environment variable with your PostgreSQL connection string
   • Format: postgresql+asyncpg://user:password@host:port/database

3. Deploy:

   vercel --prod
   

Note:

• Runtime dependencies don't include psycopg2-binary or alembic (only needed for local migrations)
• Python 3.12 is used (Vercel doesn't support 3.13 yet)
• Make sure to run migrations on your database before deploying

References

• FastAPI Documentation
• SQLAlchemy Async Documentation
• Alembic Documentation
• uv Documentation
• Vercel Python Documentation

License

MIT