Some of them also ✨ [**sponsor FastAPI**](../help-fastapi.md#sponsor-the-author){.internal-link target=_blank} ✨, this ensures the continued and healthy **development** of FastAPI and its **ecosystem**.

from fastapi import Depends, FastAPI, Security
from fastapi.security import APIKeyQuery
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()

api_key = APIKeyQuery(name="key", description="API Key Query")


class User(BaseModel):
    username: str


def get_current_user(oauth_header: str = Security(api_key)):
    user = User(username=oauth_header)
    return user


@app.get("/users/me")

from typing import Optional

from fastapi import FastAPI, Security
from fastapi.security.http import HTTPAuthorizationCredentials, HTTPBase
from fastapi.testclient import TestClient

app = FastAPI()

security = HTTPBase(scheme="Other", auto_error=False)


@app.get("/users/me")
def read_current_user(
    credentials: Optional[HTTPAuthorizationCredentials] = Security(security),
):
    if credentials is None:

from fastapi import FastAPI, Security
from fastapi.security import HTTPAuthorizationCredentials, HTTPDigest
from fastapi.testclient import TestClient

app = FastAPI()

security = HTTPDigest()


@app.get("/users/me")
def read_current_user(credentials: HTTPAuthorizationCredentials = Security(security)):
    return {"scheme": credentials.scheme, "credentials": credentials.credentials}


client = TestClient(app)

from typing import Optional

from fastapi import FastAPI, Security
from fastapi.security import OAuth2AuthorizationCodeBearer
from fastapi.testclient import TestClient

app = FastAPI()

oauth2_scheme = OAuth2AuthorizationCodeBearer(
    authorizationUrl="authorize", tokenUrl="token", auto_error=True
)


@app.get("/items/")
async def read_items(token: Optional[str] = Security(oauth2_scheme)):
    return {"token": token}

`FastAPI` est une classe Python qui fournit toutes les fonctionnalités nécessaires au lancement de votre API.

/// note | "Détails techniques"

`FastAPI` est une classe héritant directement de `Starlette`.

Vous pouvez donc aussi utiliser toutes les fonctionnalités de <a href="https://www.starlette.io/" class="external-link" target="_blank">Starlette</a> depuis `FastAPI`.

///

### Étape 2 : créer une "instance" `FastAPI`

Você também pode usá-lo para gerar código automaticamente para clientes que se comunicam com sua API. Por exemplo, aplicativos front-end, móveis ou IoT.

## Recapitulando, passo a passo

### Passo 1: importe `FastAPI`

```Python hl_lines="1"
{!../../docs_src/first_steps/tutorial001.py!}
```

from fastapi import FastAPI
from fastapi.staticfiles import StaticFiles

app = FastAPI()

from typing import Dict, List, Optional, Tuple

import pytest
from fastapi import FastAPI, Query
from pydantic import BaseModel


def test_invalid_sequence():
    with pytest.raises(AssertionError):
        app = FastAPI()

        class Item(BaseModel):
            title: str

        @app.get("/items/")
        def read_items(q: List[Item] = Query(default=None)):
            pass  # pragma: no cover

import typing

from fastapi import FastAPI
from fastapi.responses import JSONResponse
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()


class JsonApiResponse(JSONResponse):
    media_type = "application/vnd.api+json"


class Error(BaseModel):
    status: str
    title: str


class JsonApiError(BaseModel):
    errors: typing.List[Error]


@app.get(
    "/a",