```

### `HTMLResponse`

Takes some text or bytes and returns an HTML response, as you read above.

### `PlainTextResponse`

Takes some text or bytes and returns an plain text response.

```Python hl_lines="2  7  9"
{!../../../docs_src/custom_response/tutorial005.py!}
```

### `JSONResponse`

Takes some data and returns an `application/json` encoded response.

    requestBodySuccess(
      "Hello".toRequestBody("text/plain".toMediaType()),
      CoreMatchers.equalTo(5L),
      CoreMatchers.equalTo(19L),
    )
  }

  @Test
  fun requestBodySuccessHttp() {
    requestBodySuccess(
      "Hello".toRequestBody("text/plain".toMediaType()),
      CoreMatchers.equalTo(5L),
      CoreMatchers.equalTo(19L),
    )
  }

INFO: Sending request http://www.publicobject.com/helloworld.txt on null
User-Agent: OkHttp Example

INFO: Received response for https://publicobject.com/helloworld.txt in 1179.7ms
Server: nginx/1.4.6 (Ubuntu)
Content-Type: text/plain
Content-Length: 1759
Connection: keep-alive
```

We can see that we were redirected because `response.request().url()` is different from `request.url()`. The two log statements log two different URLs.

  }

  private fun response(
    url: String,
    bodyHex: ByteString,
    fn: Response.Builder.() -> Unit = {},
  ): Response {
    return Response.Builder()
      .body(bodyHex.toResponseBody("text/plain".toMediaType()))
      .code(200)
      .message("OK")
      .request(Request.Builder().url(url).build())
      .protocol(Protocol.HTTP_2)
      .apply(fn)
      .build()
  }

instead of being called directly (as it would block the server).

If you are coming from another async framework that does not work in the way described above and you are used to defining trivial compute-only *path operation functions* with plain `def` for a tiny performance gain (about 100 nanoseconds), please note that in **FastAPI** the effect would be quite opposite. In these cases, it's better to use `async def` unless your *path operation functions* use code that performs blocking <abbr...

                </mxCell>
                <mxCell id="85" value="&lt;span style=&quot;font-family: &amp;#34;roboto&amp;#34; ; font-size: 24px&quot;&gt;Plain response from: someapp.example.com&lt;/span&gt;" style="shape=hexagon;perimeter=hexagonPerimeter2;whiteSpace=wrap;html=1;fixedSize=1;strokeColor=#9673a6;strokeWidth=3;fillColor=#e1d5e7;" parent="1" vertex="1">

    connection!!.idleAtNs -= IDLE_CONNECTION_HEALTHY_NS
    Thread.sleep(250)

    val requestB =
      Request(
        url = server.url("/"),
        body = "b".toRequestBody("text/plain".toMediaType()),
      )
    val responseB = client.newCall(requestB).execute()
    assertThat(responseB.body.string()).isEqualTo("b")
    assertThat(server.takeRequest().sequenceNumber).isEqualTo(0)
  }

In these cases, it could make sense to store the tags in an `Enum`.

**FastAPI** supports that the same way as with plain strings:

```Python hl_lines="1  8-10  13  18"
{!../../../docs_src/path_operation_configuration/tutorial002b.py!}
```

## Summary and description

You can add a `summary` and `description`:

    /**
     * This type is syntactically identical to "multipart/mixed", but the semantics are different.
     * In particular, in a digest, the default `Content-Type` value for a body part is changed from
     * "text/plain" to "message/rfc822".
     */
    @JvmField
    val DIGEST = "multipart/digest".toMediaType()

    /**
     * This type is syntactically identical to "multipart/mixed", but the semantics are different.

=== "Python 3.8+"

    ```Python hl_lines="1  20"
    {!> ../../../docs_src/extra_models/tutorial004.py!}
    ```

## Response with arbitrary `dict`

You can also declare a response using a plain arbitrary `dict`, declaring just the type of the keys and values, without using a Pydantic model.

This is useful if you don't know the valid field/attribute names (that would be needed for a Pydantic model) beforehand.