# "servers":[{"url":"http://prod.test.com","description":"Production server"}],
```

## OpenAPI extensions

FastAPI allows you to add in extra OpenAPI configuration directly within your route, through the use of the `openapi_extra` parameter.
Below, we've annotated a "good" route within FastAPI that has it's typings as well as Fern extensions to assist in naming.

```python {5-9}
@router.post(
    "/your/post/endpoint",
    response_model=YourResponseModel,            #  <-- with FastAPI, it is important to specify your response model so that it comes through to the OpenAPI Specification
    summary="Get some response for your req",    #  <-- if you'd like to add a description to your endpoint, you can do so here
    openapi_extra={                              #  <-- finally, you can add in your Fern extensions here, these extensions will produce SDK code that looks something like: `client.endpoints.create(...)` in python
        "x-fern-sdk-method-name": "create",
        "x-fern-sdk-group-name": "endpoints",
        "x-fern-availability": "beta",
    },
)
async def your_post_endpoint(
    payload: YourRequestModel,
) -> YourResponseModel:
```

## Specifying examples

FastAPI allows you to specify examples for your data models, which Fern will pick up and use within your generated SDKs and documentation automatically.

For more information on leveraging examples within Fern, please refer to the [Fern documentation](/learn/api-definition/openapi/extensions/others#request--response-examples).

For more information on this FastAPI functionality, please refer to the [FastAPI documentation](https://fastapi.tiangolo.com/tutorial/schema-extra-example/).

```python {7-11}
from pydantic import BaseModel

class MyObject(BaseModel):
    id: str

    class Config:
        schema_extra = {
            "example": {
                "id": "a-cool-uuid",
            }
        }
```

## Additional customization

FastAPI has a lot of flexibility in how you can customize your OpenAPI Specification. Please refer to the [FastAPI documentation](https://fastapi.tiangolo.com/how-to/extending-openapi/#modify-the-openapi-schema) for more information.