The files will be uploaded as "form data".

If you declare the type of your *path operation function* parameter as `bytes`, **FastAPI** will read the file for you and you will receive the contents as `bytes`.

Keep in mind that this means that the whole contents will be stored in memory. This will work well for small files.

But there are several cases in which you might benefit from using `UploadFile`.

## File Parameters with `UploadFile`

For example, to declare another response with a status code `404` and a Pydantic model `Message`, you can write:

{* ../../docs_src/additional_responses/tutorial001.py hl[18,22] *}

/// note

Keep in mind that you have to return the `JSONResponse` directly.

///

/// info

The `model` key is not part of OpenAPI.

Just use any kind of model, any kind of class, any kind of database that you need for your application. **FastAPI** has you covered with the dependency injection system.

## Code size

This example might seem verbose. Keep in mind that we are mixing security, data models, utility functions and *path operations* in the same file.

But here's the key point.

The security and dependency injection stuff is written once.

     * final long[] will be a "rolling snapshot" of the state of the bit array. This is usually good
     * enough, but should be kept in mind.
     */
    public static long[] toPlainArray(AtomicLongArray atomicLongArray) {
      long[] array = new long[atomicLongArray.length()];
      for (int i = 0; i < array.length; ++i) {

Of course, there are some cases where there's no problem in running the previous steps multiple times, in that case, it's a lot easier to handle.

/// tip

Also, keep in mind that depending on your setup, in some cases you **might not even need any previous steps** before starting your application.

In that case, you wouldn't have to worry about any of this. 🤷

///

```

////

//// tab | Python 3.8+

```Python hl_lines="9"
{!> ../../docs_src/body_nested_models/tutorial009.py!}
```

////

/// tip

Keep in mind that JSON only supports `str` as keys.

But Pydantic has automatic data conversion.

Now, from a **developer's perspective**, here are several things to keep in mind while thinking about HTTPS:

* For HTTPS, **the server** needs to **have "certificates"** generated by a **third party**.
    * Those certificates are actually **acquired** from the third party, not "generated".

    assertThat(copy.columnKeySet()).containsExactlyElementsIn(original.columnKeySet()).inOrder();
  }

  @J2ktIncompatible
  @GwtIncompatible // Mind-bogglingly slow in GWT
  @AndroidIncompatible // slow
  public void testOverflowCondition() {
    // See https://github.com/google/guava/issues/1322 for details.

<img src="/img/tutorial/custom-response/image01.png">

## Available responses

Here are some of the available responses.

Keep in mind that you can use `Response` to return anything else, or even create a custom sub-class.

/// note | "Technical Details"

You could also use `from starlette.responses import HTMLResponse`.

/// tip

Some tools like Dependabot, will add some labels, like `dependencies`, but have in mind that this label is not used by the `latest-changes` GitHub Action, so it won't be used in the release notes. Please make sure one of the labels above is added.

///

## Add Labels to Translation PRs