Does FastAPI Work With Neon?
FastAPI and Neon work seamlessly together—FastAPI handles your API logic while Neon provides a serverless PostgreSQL backend with excellent connection pooling support.
Quick Facts
How FastAPI Works With Neon
FastAPI and Neon are a natural pairing for building modern Python APIs. Neon provides a PostgreSQL database with built-in connection pooling via pgBouncer, which is critical for FastAPI applications since each request might spawn new connections. You connect FastAPI to Neon using standard PostgreSQL drivers like psycopg2 or asyncpg, with the connection string provided by Neon's dashboard. The async nature of FastAPI pairs exceptionally well with asyncpg, allowing non-blocking database queries that won't starve your event loop. Neon's branching feature is particularly useful during development—create isolated database branches for testing without affecting production data. The serverless scaling of Neon means your database automatically handles traffic spikes, while FastAPI's lightweight nature means you can deploy on any serverless platform (Vercel, Railway, Render) or traditional servers. The main consideration is connection limits: Neon's free tier includes a reasonable pool size, but high-concurrency applications may need to tune your connection pool settings or upgrade.
Best Use Cases
Quick Setup
pip install fastapi asyncpg sqlalchemy python-dotenv uvicornfrom fastapi import FastAPI
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession
from sqlalchemy.orm import sessionmaker
import os
DATABASE_URL = os.getenv("DATABASE_URL").replace("postgresql://", "postgresql+asyncpg://")
engine = create_async_engine(DATABASE_URL, echo=False, pool_size=20, max_overflow=0)
AsyncSessionLocal = sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
app = FastAPI()
async def get_db():
async with AsyncSessionLocal() as session:
yield session
@app.get("/items")
async def get_items(db: AsyncSession = Depends(get_db)):
result = await db.execute("SELECT * FROM items LIMIT 10")
return {"items": result.fetchall()}
if __name__ == "__main__":
import uvicorn
uvicorn.run(app, host="0.0.0.0", port=8000)Known Issues & Gotchas
Connection pool exhaustion under high concurrency
Fix: Use asyncpg with proper pool configuration (min_size=10, max_size=20) and ensure FastAPI's connection context managers properly close connections. Monitor Neon's connection dashboard.
Cold starts on serverless platforms can timeout if database initialization is slow
Fix: Use connection pooling, lazy initialization, and keep database setup lightweight. Test cold start times before production deployment.
Neon free tier resets after 7 days of inactivity
Fix: Not a problem for active projects, but set up a simple health check endpoint if your API might have idle periods.
Alternatives
- •Django + Neon: More batteries-included but heavier; better for larger projects with complex admin panels
- •Node.js/Express + Neon: Lighter weight, faster startup times; good alternative if you prefer JavaScript
- •FastAPI + Supabase: Includes auth and real-time subscriptions out of the box, but less flexibility on raw SQL
Resources
Related Compatibility Guides
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