"description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {

                "responses": {
                    "200": {
                        "content": {"application/json": {"schema": {}}},
                        "description": "Successful " "Response",
                    },
                    "422": {
                        "content": {
                            "application/json": {
                                "schema": {

                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {

                    "summary": "Create Item",
                    "operationId": "create_item_items__post",
                    "requestBody": {
                        "content": {
                            "application/x-yaml": {
                                "schema": {
                                    "title": "Item",
                                    "required": ["name", "tags"],
                                    "type": "object",

                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {

                    "responses": {
                        "200": {
                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        }
                    },
                }
            }
        },

from typing import Any

import orjson
from fastapi import FastAPI, Response

app = FastAPI()


class CustomORJSONResponse(Response):
    media_type = "application/json"

    def render(self, content: Any) -> bytes:
        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():

<span style="color: green;">INFO</span>:     Started server process [28722]
<span style="color: green;">INFO</span>:     Waiting for application startup.
<span style="color: green;">INFO</span>:     Application startup complete.
```

</div>

/// note | "Nota"

O comando `uvicorn main:app` se refere a:

* `main`: o arquivo `main.py` (o "módulo" Python).

            public void invoke(TestBrowser browser) {
                browser.goTo("http://localhost:3333");
                assertThat(browser.pageSource()).contains("Your new application is ready.");
            }
        });
    }

There's a whole chapter here in the documentation about it, you can read it at [Additional Responses in OpenAPI](additional-responses.md){.internal-link target=_blank}.

## OpenAPI Extra

When you declare a *path operation* in your application, **FastAPI** automatically generates the relevant metadata about that *path operation* to be included in the OpenAPI schema.

/// note | "Technical details"