The main tasks that you can do right now are:

* [Help others with questions in GitHub](#help-others-with-questions-in-github){.internal-link target=_blank} (see the section above).
* [Review Pull Requests](#review-pull-requests){.internal-link target=_blank} (see the section above).

Those two tasks are what **consume time the most**. That's the main work of maintaining FastAPI.

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:single">main.py</u>
<font color="#3465A4">INFO    </font> Using path <font color="#3465A4">main.py</font>
<font color="#3465A4">INFO    </font> Resolved absolute path <font color="#75507B">/home/user/code/awesomeapp/</font><font color="#AD7FA8">main.py</font>

Найпростіший файл FastAPI може виглядати так:

{* ../../docs_src/first_steps/tutorial001.py *}

Скопіюйте це до файлу `main.py`.

Запустіть сервер:

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:single">main.py</u>
<font color="#3465A4">INFO    </font> Using path <font color="#3465A4">main.py</font>

<div class="termy">

```console
// Ở đây chúng ta chưa cài đặt biến môi trường
$ python main.py

// Vì chúng ta chưa cài đặt biến môi trường, chúng ta nhận được giá trị mặc định

Hello World from Python

// Nhưng nếu chúng ta tạo một biến môi trường trước đó
$ export MY_NAME="Wade Wilson"

// Và sau đó gọi chương trình lại
$ python main.py

// Bây giờ nó có thể đọc biến môi trường

Hello Wade Wilson from Python
```

Припустимо, у Вас є структура файлів, описана в розділі [Більші застосунки](bigger-applications.md){.internal-link target=_blank}:

```
.
├── app
│   ├── __init__.py
│   └── main.py
```
У файлі `main.py` знаходиться Ваш застосунок **FastAPI** :

{* ../../docs_src/app_testing/main.py *}

### Файл тестування

<div class="termy">

```console
// Here we don't set the env var yet
$ python main.py

// As we didn't set the env var, we get the default value

Hello World from Python

// But if we create an environment variable first
$ export MY_NAME="Wade Wilson"

// And then call the program again
$ python main.py

// Now it can read the environment variable

Hello Wade Wilson from Python
```

   <span style="background-color:#007166"><font color="#D3D7CF"> module </font></span>  🐍 main.py

     <span style="background-color:#007166"><font color="#D3D7CF"> code </font></span>  Importing the FastAPI app object from the module with the
             following code:

```
.
├── app
│   ├── __init__.py
│   └── main.py
```

In the file `main.py` you have your **FastAPI** app:


{* ../../docs_src/app_testing/main.py *}

### Testing file { #testing-file }

   * X-Device-Referer}</a> header field name. Header used for VAST requests to provide the {@link
   * #REFERER} header value that the on-behalf-of client would have used when making a request
   * itself.
   *
   * @since 31.0
   */
  public static final String X_DEVICE_REFERER = "X-Device-Referer";

  /**
   * The HTTP <a

            params {
                // Disable jdk-provider-plugin, otherwise the JAVA_HOME will be overwritten
                // https://github.com/gradle/teamcity-jdk-provider-plugin/blob/main/teamcity-jdk-provider-plugin-agent/src/main/kotlin/org/gradle/teamcity_jdk_provider_plugin/JdkProviderAgentLifecycleListener.kt#L22
                param("JdkProviderEnabled", "false")
                // should be the same version we run TeamCity with