Does FastAPI Work With SQLite?
FastAPI and SQLite work excellently together for building lightweight, production-ready APIs with zero database setup overhead.
Quick Facts
How FastAPI Works With SQLite
FastAPI doesn't have built-in database support, but SQLite integrates seamlessly through ORM libraries like SQLAlchemy or Tortoise-ORM, which FastAPI's creator explicitly endorses. You define models in Python, SQLAlchemy handles the SQL generation, and FastAPI's dependency injection system passes database sessions to route handlers cleanly. The combination is ideal for prototypes, small-to-medium projects, and edge deployments because SQLite requires no separate server—the database is just a file on disk. FastAPI's async support pairs well with async SQLAlchemy (via sqlalchemy[asyncio]) for non-blocking database queries. For concurrent writes or high-traffic APIs, SQLite becomes a bottleneck since it locks the entire database during writes, making PostgreSQL/MySQL better choices at scale. Most developers use SQLAlchemy Core or the ORM layer with FastAPI's Depends() for clean, testable database access patterns.
Best Use Cases
Quick Setup
pip install fastapi uvicorn sqlalchemyfrom fastapi import FastAPI, Depends
from sqlalchemy import create_engine, Column, Integer, String
from sqlalchemy.orm import declarative_base, sessionmaker, Session
engine = create_engine("sqlite:///./test.db")
Base = declarative_base()
class User(Base):
__tablename__ = "users"
id = Column(Integer, primary_key=True)
name = Column(String)
Base.metadata.create_all(bind=engine)
SessionLocal = sessionmaker(bind=engine)
def get_db():
db = SessionLocal()
try:
yield db
finally:
db.close()
app = FastAPI()
@app.post("/users/")
def create_user(name: str, db: Session = Depends(get_db)):
user = User(name=name)
db.add(user)
db.commit()
return user
@app.get("/users/{user_id}")
def get_user(user_id: int, db: Session = Depends(get_db)):
return db.query(User).filter(User.id == user_id).first()Known Issues & Gotchas
SQLite locks during writes, blocking concurrent requests
Fix: Use SQLite only for low-concurrency scenarios (<10 concurrent users). Migrate to PostgreSQL/MySQL for production APIs with heavy write loads. Enable WAL (Write-Ahead Logging) mode for modest concurrency improvements.
Async SQLAlchemy requires sqlalchemy[asyncio] extra; standard SQLite driver is sync-only
Fix: Install 'pip install sqlalchemy[asyncio]' and use aiosqlite. Or accept sync queries in async routes (they'll block the event loop but work fine for light traffic).
SQLite doesn't enforce foreign key constraints by default
Fix: Execute 'PRAGMA foreign_keys = ON' in your database initialization to enable constraint enforcement.
Database file location confusion in deployed containers
Fix: Use absolute paths or environment variables for database location. Ensure the FastAPI process has write permissions to the directory.
Alternatives
- •FastAPI + PostgreSQL: Better for production, supports concurrent writes and advanced features
- •FastAPI + MongoDB: Document-oriented database, useful for unstructured data and rapid schema evolution
- •FastAPI + DynamoDB: Serverless option for AWS deployments without managing database infrastructure
Resources
Related Compatibility Guides
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