Does FastAPI Work With MySQL?
FastAPI and MySQL work together seamlessly through SQLAlchemy ORM or direct database drivers, making them an excellent choice for production APIs.
Quick Facts
How FastAPI Works With MySQL
FastAPI doesn't have a built-in MySQL driver, but it integrates perfectly with SQLAlchemy ORM (recommended) or mysql-connector-python for direct connections. The standard approach uses SQLAlchemy as the ORM layer with a MySQL dialect, allowing you to define models declaratively and leverage FastAPI's dependency injection system for database sessions. This pairing is particularly clean because FastAPI's async support can work with async SQLAlchemy drivers like aiomysql or asyncmy, enabling non-blocking database operations that scale well. Most developers use SQLAlchemy 2.0+ with FastAPI, managing database connections through FastAPI's dependency injection system, which handles session lifecycle automatically. The developer experience is excellent: you define Pydantic models for request/response validation and SQLAlchemy models for database persistence, keeping concerns cleanly separated. Connection pooling is critical and handled transparently by SQLAlchemy's engine configuration.
Best Use Cases
Quick Setup
pip install fastapi sqlalchemy asyncmy uvicornfrom fastapi import FastAPI, Depends
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy.orm import declarative_base
from sqlalchemy import Column, Integer, String
DATABASE_URL = "mysql+asyncmy://user:password@localhost/dbname"
engine = create_async_engine(DATABASE_URL, echo=True)
AsyncSessionLocal = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
Base = declarative_base()
class User(Base):
__tablename__ = "users"
id = Column(Integer, primary_key=True)
name = Column(String(50))
app = FastAPI()
async def get_db():
async with AsyncSessionLocal() as session:
yield session
@app.get("/users/{user_id}")
async def get_user(user_id: int, db: AsyncSession = Depends(get_db)):
result = await db.execute("SELECT * FROM users WHERE id = ?", [user_id])
return result.first()Known Issues & Gotchas
Blocking database operations can starve async event loop if using synchronous SQLAlchemy with FastAPI's async routes
Fix: Use asyncmy or aiomysql drivers with SQLAlchemy's async engine, or run sync operations in thread pool with run_in_threadpool()
Connection pool exhaustion under load due to improper session management
Fix: Always use dependency injection for session management; ensure sessions are closed after each request using context managers or FastAPI's Depends()
N+1 query problems when lazy-loading relationships in loops
Fix: Use SQLAlchemy's selectinload() or joinedload() strategies in queries to eagerly load relationships
MySQL default charset issues causing encoding problems with emoji or special characters
Fix: Specify charset=utf8mb4 in database URL and ensure MySQL tables use utf8mb4_unicode_ci collation
Alternatives
- •PostgreSQL + SQLAlchemy: More advanced features (JSON support, arrays) with identical FastAPI integration
- •MongoDB + Motor: Document-oriented alternative for unstructured data with native async Python support
- •SQLite + SQLAlchemy: Development/testing alternative with zero setup, not recommended for production
Resources
Related Compatibility Guides
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