Does FastAPI Work With PlanetScale?
FastAPI and PlanetScale work together seamlessly—use any MySQL ORM (SQLAlchemy, Tortoise-ORM) with PlanetScale's connection string to build production-ready APIs.
Quick Facts
How FastAPI Works With PlanetScale
FastAPI is database-agnostic and works with any Python ORM that supports MySQL. PlanetScale provides a standard MySQL-compatible connection string (with or without SSL), so integration is straightforward: install an ORM like SQLAlchemy, configure the PlanetScale DSN, and use FastAPI's dependency injection to manage database sessions across routes. The developer experience is smooth—PlanetScale's serverless nature means no connection pooling overhead on your end (they handle it), and FastAPI's async support pairs well with async SQLAlchemy for non-blocking database I/O. One architectural consideration: PlanetScale enforces FOREIGN KEY constraints by default in newer versions, which can affect schema design. Also, their branching feature is powerful for testing schema migrations without affecting production, making it excellent for iterative API development. Connection timeouts are rare but happen during database restarts—implement basic retry logic in your ORM configuration.
Best Use Cases
FastAPI + PlanetScale with SQLAlchemy
pip install fastapi sqlalchemy pymysql uvicornfrom fastapi import FastAPI, Depends
from sqlalchemy import create_engine, Column, Integer, String
from sqlalchemy.orm import declarative_base, sessionmaker, Session
# PlanetScale connection string from .env
DATABASE_URL = "mysql+pymysql://user:pass@aws.connect.psdb.cloud/dbname?charset=utf8mb4&sslaccept=strict"
engine = create_engine(DATABASE_URL, pool_pre_ping=True, pool_recycle=3600)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
Base = declarative_base()
class User(Base):
__tablename__ = "users"
id = Column(Integer, primary_key=True)
name = Column(String)
Base.metadata.create_all(bind=engine)
app = FastAPI()
def get_db():
db = SessionLocal()
try:
yield db
finally:
db.close()
@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
PlanetScale connections may timeout after 15 minutes of inactivity
Fix: Configure connection pool with `pool_pre_ping=True` and set reasonable pool_recycle (e.g., 3600s) in SQLAlchemy
FOREIGN KEY constraint enforcement enabled by default can break INSERT operations without proper cascade setup
Fix: Review PlanetScale docs on foreign keys, use `ON DELETE CASCADE` clauses, or disable enforcement during development branches
Connection string includes `?sslaccept=strict` by default—some older MySQL drivers may fail
Fix: Ensure you're using modern drivers like `pymysql` or `aiomysql`; update to latest versions
Query Plan Insights and analytics available in PlanetScale don't integrate directly with FastAPI logging
Fix: Manually log slow queries or use third-party APM tools like Sentry/Datadog for observability
Alternatives
- •Django + PlanetScale: Full-featured web framework with built-in ORM, admin panel, and migrations—better for monolithic apps
- •Node.js (Express/Prisma) + PlanetScale: Prisma has excellent PlanetScale integration with native branch awareness
- •Python (Flask) + PostgreSQL (Neon): Lighter alternative to FastAPI with cloud Postgres instead of MySQL, similar branching features
Resources
Related Compatibility Guides
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