Why FastAPI
FastAPI is a modern Python web framework that leans on type hints, Pydantic models, and OpenAPI generation. It is productive for API-heavy services because validation, documentation, and editor feedback share the same source of truth.
Service Shape
A good FastAPI service keeps handlers thin. Request parsing, authorization, business logic, and persistence should live behind clear boundaries.
from fastapi import FastAPI
from pydantic import BaseModel
app = FastAPI()
class CreateUserRequest(BaseModel):
email: str
name: str
@app.post("/users")
async def create_user(request: CreateUserRequest):
return {"email": request.email, "name": request.name}Performance Notes
Async endpoints help when the service waits on network calls. They do not make CPU-bound Python code faster. Measure the bottleneck first, then choose workers, queues, caches, or async I/O based on evidence.