The simplest FastAPI file could look like this:

{* ../../docs_src/first_steps/tutorial001_py39.py *}

Copy that to a file `main.py`.

Run the live server:

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:solid">main.py</u>

  <span style="background-color:#009485"><font color="#D3D7CF"> FastAPI </font></span>  Starting development server 🚀

* (Optionnellement) comprendre ce que vous, en tant que développeur, devez savoir sur HTTPS.
* Configurer un cluster en mode Docker Swarm avec HTTPS automatique, même sur un simple serveur à 5 dollars US/mois. En environ **20 min**.
* Générer et déployer une application **FastAPI** complète, en utilisant votre cluster Docker Swarm, avec HTTPS, etc. En environ **10 min**.

from fastapi.testclient import TestClient

from .config import Settings
from .main import app, get_settings

client = TestClient(app)


def get_settings_override():
    return Settings(admin_email="******@****.***")


app.dependency_overrides[get_settings] = get_settings_override


def test_app():
    response = client.get("/info")
    data = response.json()
    assert data == {
        "app_name": "Awesome API",

    client.newCall(request).execute().use { response ->
      if (!response.isSuccessful) throw IOException("Unexpected code $response")

      println(response.body.string())
    }
  }
}

fun main() {
  Authenticate().run()

// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package main

import (
	"crypto/rsa"
	"crypto/x509"
	"encoding/base64"
	"encoding/pem"
	"log"
)

func bytesToPrivateKey(priv []byte) (*rsa.PrivateKey, error) {
	// Try PEM

        assert orjson is not None, "orjson must be installed"
        return orjson.dumps(content, option=orjson.OPT_INDENT_2)


@app.get("/", response_class=CustomORJSONResponse)
async def main():

                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        }
                    },
                    "summary": "Read Main",
                    "operationId": "read_main__get",
                }
            }
        },

// TODO these accessors should be generated - https://github.com/gradle/gradle/issues/3191

val Project.kotlinMainSourceSet: SourceDirectorySet

name: golangci-lint
on:
  push:
    branches:
      - main
      - master
  pull_request:

permissions:
  contents: read
  pull-requests: read

jobs:
  golangci:
    name: lint
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-go@v5
        with:
          go-version: stable
      - name: golangci-lint
        uses: golangci/golangci-lint-action@v7

<span style="color: green;">INFO</span>:     Application startup complete.
```

</div>

/// note | 備考

`uvicorn main:app`は以下を示します:

* `main`: `main.py`ファイル (Python "module")。
* `app`:  `main.py`内部で作られるobject（`app = FastAPI()`のように記述される）。
* `--reload`: コードの変更時にサーバーを再起動させる。開発用。

///

出力には次のような行があります:

```hl_lines="4"