FastAPI

Common errors

Warnings

Install

Install compatibility verified last tested: 2026-05-12

Imports

• FastAPI

  from fastapi import FastAPI

• Depends

  from fastapi import Depends

• HTTPException

  from fastapi import HTTPException

• status
  wrong

  from starlette import status

  correct

  from fastapi import status

  While `starlette.status` works, `fastapi.status` is the officially exposed and preferred import path.

• Body

  from fastapi import Body

• Query

  from fastapi import Query

• Path

  from fastapi import Path

• Response
  wrong

  from starlette.responses import Response

  correct

  from fastapi import Response

  FastAPI re-exports common Starlette components for convenience; using `fastapi.Response` is generally preferred.

Quickstart verified last tested: 2026-04-23

This quickstart demonstrates a basic FastAPI application with two GET endpoints. It defines a root endpoint and an endpoint with a path parameter and an optional query parameter. The accompanying `uvicorn` command shows how to run the application for development.

import uvicorn
from fastapi import FastAPI

app = FastAPI()

@app.get("/")
async def read_root():
    return {"Hello": "World"}

@app.get("/items/{item_id}")
async def read_item(item_id: int, q: str | None = None):
    return {"item_id": item_id, "q": q}

# To run this app:
# 1. Save it as main.py
# 2. Run from your terminal: uvicorn main:app --reload
# Then open http://127.0.0.1:8000/ or http://127.0.0.1:8000/docs