OpenAPI docs

Utilities to handle OpenAPI automatic UI documentation, including Swagger UI (by default at /docs), ReDoc (by default at /redoc) & Scalar (by default at /scalar).

fastapi.openapi.docs.get_swagger_ui_html

get_swagger_ui_html(
    *,
    openapi_url,
    title,
    swagger_js_url="https://cdn.jsdelivr.net/npm/swagger-ui-dist@5.9.0/swagger-ui-bundle.js",
    swagger_css_url="https://cdn.jsdelivr.net/npm/swagger-ui-dist@5.9.0/swagger-ui.css",
    swagger_favicon_url="https://fastapi.tiangolo.com/img/favicon.png",
    oauth2_redirect_url=None,
    init_oauth=None,
    swagger_ui_parameters=None
)

Generate and return the HTML that loads Swagger UI for the interactive API docs (normally served at /docs).

You would only call this function yourself if you needed to override some parts, for example the URLs to use to load Swagger UI's JavaScript and CSS.

Read more about it in the FastAPI docs for Configure Swagger UI and the FastAPI docs for Custom Docs UI Static Assets (Self-Hosting).

PARAMETER	DESCRIPTION
openapi_url	The OpenAPI URL that Swagger UI should load and use. This is normally done automatically by FastAPI using the default URL /openapi.json. TYPE: str
title	The HTML <title> content, normally shown in the browser tab. TYPE: str
swagger_js_url	The URL to use to load the Swagger UI JavaScript. It is normally set to a CDN URL. TYPE: str DEFAULT: 'https://cdn.jsdelivr.net/npm/swagger-ui-dist@5.9.0/swagger-ui-bundle.js'
swagger_css_url	The URL to use to load the Swagger UI CSS. It is normally set to a CDN URL. TYPE: str DEFAULT: 'https://cdn.jsdelivr.net/npm/swagger-ui-dist@5.9.0/swagger-ui.css'
swagger_favicon_url	The URL of the favicon to use. It is normally shown in the browser tab. TYPE: str DEFAULT: 'https://fastapi.tiangolo.com/img/favicon.png'
oauth2_redirect_url	The OAuth2 redirect URL, it is normally automatically handled by FastAPI. TYPE: Optional[str] DEFAULT: None
init_oauth	A dictionary with Swagger UI OAuth2 initialization configurations. TYPE: Optional[Dict[str, Any]] DEFAULT: None
swagger_ui_parameters	Configuration parameters for Swagger UI. It defaults to swagger_ui_default_parameters. TYPE: Optional[Dict[str, Any]] DEFAULT: None

Source code in fastapi/openapi/docs.py

def get_swagger_ui_html(
    *,
    openapi_url: Annotated[
        str,
        Doc(
            """
            The OpenAPI URL that Swagger UI should load and use.

            This is normally done automatically by FastAPI using the default URL
            `/openapi.json`.
            """
        ),
    ],
    title: Annotated[
        str,
        Doc(
            """
            The HTML `<title>` content, normally shown in the browser tab.
            """
        ),
    ],
    swagger_js_url: Annotated[
        str,
        Doc(
            """
            The URL to use to load the Swagger UI JavaScript.

            It is normally set to a CDN URL.
            """
        ),
    ] = "https://cdn.jsdelivr.net/npm/swagger-ui-dist@5.9.0/swagger-ui-bundle.js",
    swagger_css_url: Annotated[
        str,
        Doc(
            """
            The URL to use to load the Swagger UI CSS.

            It is normally set to a CDN URL.
            """
        ),
    ] = "https://cdn.jsdelivr.net/npm/swagger-ui-dist@5.9.0/swagger-ui.css",
    swagger_favicon_url: Annotated[
        str,
        Doc(
            """
            The URL of the favicon to use. It is normally shown in the browser tab.
            """
        ),
    ] = "https://fastapi.tiangolo.com/img/favicon.png",
    oauth2_redirect_url: Annotated[
        Optional[str],
        Doc(
            """
            The OAuth2 redirect URL, it is normally automatically handled by FastAPI.
            """
        ),
    ] = None,
    init_oauth: Annotated[
        Optional[Dict[str, Any]],
        Doc(
            """
            A dictionary with Swagger UI OAuth2 initialization configurations.
            """
        ),
    ] = None,
    swagger_ui_parameters: Annotated[
        Optional[Dict[str, Any]],
        Doc(
            """
            Configuration parameters for Swagger UI.

            It defaults to [swagger_ui_default_parameters][fastapi.openapi.docs.swagger_ui_default_parameters].
            """
        ),
    ] = None,
) -> HTMLResponse:
    """
    Generate and return the HTML  that loads Swagger UI for the interactive
    API docs (normally served at `/docs`).

    You would only call this function yourself if you needed to override some parts,
    for example the URLs to use to load Swagger UI's JavaScript and CSS.

    Read more about it in the
    [FastAPI docs for Configure Swagger UI](https://fastapi.tiangolo.com/how-to/configure-swagger-ui/)
    and the [FastAPI docs for Custom Docs UI Static Assets (Self-Hosting)](https://fastapi.tiangolo.com/how-to/custom-docs-ui-assets/).
    """
    current_swagger_ui_parameters = swagger_ui_default_parameters.copy()
    if swagger_ui_parameters:
        current_swagger_ui_parameters.update(swagger_ui_parameters)

    html = f"""
    <!DOCTYPE html>
    <html>
    <head>
    <link type="text/css" rel="stylesheet" href="{swagger_css_url}">
    <link rel="shortcut icon" href="{swagger_favicon_url}">
    <title>{title}</title>
    </head>
    <body>
    <div id="swagger-ui">
    </div>
    <script src="{swagger_js_url}"></script>
    <!-- `SwaggerUIBundle` is now available on the page -->
    <script>
    const ui = SwaggerUIBundle({{
        url: '{openapi_url}',
    """

    for key, value in current_swagger_ui_parameters.items():
        html += f"{json.dumps(key)}: {json.dumps(jsonable_encoder(value))},\n"

    if oauth2_redirect_url:
        html += f"oauth2RedirectUrl: window.location.origin + '{oauth2_redirect_url}',"

    html += """
    presets: [
        SwaggerUIBundle.presets.apis,
        SwaggerUIBundle.SwaggerUIStandalonePreset
        ],
    })"""

    if init_oauth:
        html += f"""
        ui.initOAuth({json.dumps(jsonable_encoder(init_oauth))})
        """

    html += """
    </script>
    </body>
    </html>
    """
    return HTMLResponse(html)

fastapi.openapi.docs.get_redoc_html

get_redoc_html(
    *,
    openapi_url,
    title,
    redoc_js_url="https://cdn.jsdelivr.net/npm/redoc@next/bundles/redoc.standalone.js",
    redoc_favicon_url="https://fastapi.tiangolo.com/img/favicon.png",
    with_google_fonts=True
)

Generate and return the HTML response that loads ReDoc for the alternative API docs (normally served at /redoc).

You would only call this function yourself if you needed to override some parts, for example the URLs to use to load ReDoc's JavaScript and CSS.

Read more about it in the FastAPI docs for Custom Docs UI Static Assets (Self-Hosting).

PARAMETER	DESCRIPTION
openapi_url	The OpenAPI URL that ReDoc should load and use. This is normally done automatically by FastAPI using the default URL /openapi.json. TYPE: str
title	The HTML <title> content, normally shown in the browser tab. TYPE: str
redoc_js_url	The URL to use to load the ReDoc JavaScript. It is normally set to a CDN URL. TYPE: str DEFAULT: 'https://cdn.jsdelivr.net/npm/redoc@next/bundles/redoc.standalone.js'
redoc_favicon_url	The URL of the favicon to use. It is normally shown in the browser tab. TYPE: str DEFAULT: 'https://fastapi.tiangolo.com/img/favicon.png'
with_google_fonts	Load and use Google Fonts. TYPE: bool DEFAULT: True

Source code in fastapi/openapi/docs.py

def get_redoc_html(
    *,
    openapi_url: Annotated[
        str,
        Doc(
            """
            The OpenAPI URL that ReDoc should load and use.

            This is normally done automatically by FastAPI using the default URL
            `/openapi.json`.
            """
        ),
    ],
    title: Annotated[
        str,
        Doc(
            """
            The HTML `<title>` content, normally shown in the browser tab.
            """
        ),
    ],
    redoc_js_url: Annotated[
        str,
        Doc(
            """
            The URL to use to load the ReDoc JavaScript.

            It is normally set to a CDN URL.
            """
        ),
    ] = "https://cdn.jsdelivr.net/npm/redoc@next/bundles/redoc.standalone.js",
    redoc_favicon_url: Annotated[
        str,
        Doc(
            """
            The URL of the favicon to use. It is normally shown in the browser tab.
            """
        ),
    ] = "https://fastapi.tiangolo.com/img/favicon.png",
    with_google_fonts: Annotated[
        bool,
        Doc(
            """
            Load and use Google Fonts.
            """
        ),
    ] = True,
) -> HTMLResponse:
    """
    Generate and return the HTML response that loads ReDoc for the alternative
    API docs (normally served at `/redoc`).

    You would only call this function yourself if you needed to override some parts,
    for example the URLs to use to load ReDoc's JavaScript and CSS.

    Read more about it in the
    [FastAPI docs for Custom Docs UI Static Assets (Self-Hosting)](https://fastapi.tiangolo.com/how-to/custom-docs-ui-assets/).
    """
    html = f"""
    <!DOCTYPE html>
    <html>
    <head>
    <title>{title}</title>
    <!-- needed for adaptive design -->
    <meta charset="utf-8"/>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    """
    if with_google_fonts:
        html += """
    <link href="https://fonts.googleapis.com/css?family=Montserrat:300,400,700|Roboto:300,400,700" rel="stylesheet">
    """
    html += f"""
    <link rel="shortcut icon" href="{redoc_favicon_url}">
    <!--
    ReDoc doesn't change outer page styles
    -->
    <style>
      body {{
        margin: 0;
        padding: 0;
      }}
    </style>
    </head>
    <body>
    <noscript>
        ReDoc requires Javascript to function. Please enable it to browse the documentation.
    </noscript>
    <redoc spec-url="{openapi_url}"></redoc>
    <script src="{redoc_js_url}"> </script>
    </body>
    </html>
    """
    return HTMLResponse(html)

fastapi.openapi.docs.get_scalar_html

get_scalar_html(
    *,
    openapi_url,
    title,
    scalar_js_url="https://cdn.jsdelivr.net/npm/@scalar/api-reference",
    scalar_proxy_url="",
    scalar_favicon_url="https://fastapi.tiangolo.com/img/favicon.png"
)

Generate and return the HTML response that loads Scalar for the alternative API docs (normally served at /scalar).

You would only call this function yourself if you needed to override some parts, for example the URLs to use to load Scalar's JavaScript and CSS.

Read more about it in the FastAPI docs for Custom Docs UI Static Assets (Self-Hosting).

PARAMETER	DESCRIPTION
openapi_url	The OpenAPI URL that Scalar should load and use. This is normally done automatically by FastAPI using the default URL /openapi.json. TYPE: str
title	The HTML <title> content, normally shown in the browser tab. TYPE: str
scalar_js_url	The URL to use to load the Scalar JavaScript. It is normally set to a CDN URL. TYPE: str DEFAULT: 'https://cdn.jsdelivr.net/npm/@scalar/api-reference'
scalar_proxy_url	The URL to use to set the Scalar Proxy. It is normally set to a Scalar API URL (https://api.scalar.com/request-proxy), but default is empty TYPE: str DEFAULT: ''
scalar_favicon_url	The URL of the favicon to use. It is normally shown in the browser tab. TYPE: str DEFAULT: 'https://fastapi.tiangolo.com/img/favicon.png'

Source code in fastapi/openapi/docs.py

def get_scalar_html(
    *,
    openapi_url: Annotated[
        str,
        Doc(
            """
            The OpenAPI URL that Scalar should load and use.

            This is normally done automatically by FastAPI using the default URL
            `/openapi.json`.
            """
        ),
    ],
    title: Annotated[
        str,
        Doc(
            """
            The HTML `<title>` content, normally shown in the browser tab.
            """
        ),
    ],
    scalar_js_url: Annotated[
        str,
        Doc(
            """
            The URL to use to load the Scalar JavaScript.

            It is normally set to a CDN URL.
            """
        ),
    ] = "https://cdn.jsdelivr.net/npm/@scalar/api-reference",
    scalar_proxy_url: Annotated[
        str,
        Doc(
            """
            The URL to use to set the Scalar Proxy.

            It is normally set to a Scalar API URL (https://api.scalar.com/request-proxy), but default is empty
            """
        ),
    ] = "",
    scalar_favicon_url: Annotated[
        str,
        Doc(
            """
            The URL of the favicon to use. It is normally shown in the browser tab.
            """
        ),
    ] = "https://fastapi.tiangolo.com/img/favicon.png",
) -> HTMLResponse:
    """
    Generate and return the HTML response that loads Scalar for the alternative
    API docs (normally served at `/scalar`).

    You would only call this function yourself if you needed to override some parts,
    for example the URLs to use to load Scalar's JavaScript and CSS.

    Read more about it in the
    [FastAPI docs for Custom Docs UI Static Assets (Self-Hosting)](https://fastapi.tiangolo.com/how-to/custom-docs-ui-assets/).
    """
    html = f"""
    <!DOCTYPE html>
    <html>
    <head>
    <title>{title}</title>
    <!-- needed for adaptive design -->
    <meta charset="utf-8"/>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="shortcut icon" href="{scalar_favicon_url}">
    <style>
      body {{
        margin: 0;
        padding: 0;
      }}
    </style>
    </head>
    <body>
    <noscript>
        Scalar requires Javascript to function. Please enable it to browse the documentation.
    </noscript>
    <script
      id="api-reference"
      data-url="{openapi_url}"
      data-proxy-url="{scalar_proxy_url}"></script>
    <script src="{scalar_js_url}"></script>
    </body>
    </html>
    """
    return HTMLResponse(html)

fastapi.openapi.docs.get_swagger_ui_oauth2_redirect_html

get_swagger_ui_oauth2_redirect_html()

Generate the HTML response with the OAuth2 redirection for Swagger UI.

You normally don't need to use or change this.

Source code in fastapi/openapi/docs.py

def get_swagger_ui_oauth2_redirect_html() -> HTMLResponse:
    """
    Generate the HTML response with the OAuth2 redirection for Swagger UI.

    You normally don't need to use or change this.
    """
    # copied from https://github.com/swagger-api/swagger-ui/blob/v4.14.0/dist/oauth2-redirect.html
    html = """
    <!doctype html>
    <html lang="en-US">
    <head>
        <title>Swagger UI: OAuth2 Redirect</title>
    </head>
    <body>
    <script>
        'use strict';
        function run () {
            var oauth2 = window.opener.swaggerUIRedirectOauth2;
            var sentState = oauth2.state;
            var redirectUrl = oauth2.redirectUrl;
            var isValid, qp, arr;

            if (/code|token|error/.test(window.location.hash)) {
                qp = window.location.hash.substring(1).replace('?', '&');
            } else {
                qp = location.search.substring(1);
            }

            arr = qp.split("&");
            arr.forEach(function (v,i,_arr) { _arr[i] = '"' + v.replace('=', '":"') + '"';});
            qp = qp ? JSON.parse('{' + arr.join() + '}',
                    function (key, value) {
                        return key === "" ? value : decodeURIComponent(value);
                    }
            ) : {};

            isValid = qp.state === sentState;

            if ((
              oauth2.auth.schema.get("flow") === "accessCode" ||
              oauth2.auth.schema.get("flow") === "authorizationCode" ||
              oauth2.auth.schema.get("flow") === "authorization_code"
            ) && !oauth2.auth.code) {
                if (!isValid) {
                    oauth2.errCb({
                        authId: oauth2.auth.name,
                        source: "auth",
                        level: "warning",
                        message: "Authorization may be unsafe, passed state was changed in server. The passed state wasn't returned from auth server."
                    });
                }

                if (qp.code) {
                    delete oauth2.state;
                    oauth2.auth.code = qp.code;
                    oauth2.callback({auth: oauth2.auth, redirectUrl: redirectUrl});
                } else {
                    let oauthErrorMsg;
                    if (qp.error) {
                        oauthErrorMsg = "["+qp.error+"]: " +
                            (qp.error_description ? qp.error_description+ ". " : "no accessCode received from the server. ") +
                            (qp.error_uri ? "More info: "+qp.error_uri : "");
                    }

                    oauth2.errCb({
                        authId: oauth2.auth.name,
                        source: "auth",
                        level: "error",
                        message: oauthErrorMsg || "[Authorization failed]: no accessCode received from the server."
                    });
                }
            } else {
                oauth2.callback({auth: oauth2.auth, token: qp, isValid: isValid, redirectUrl: redirectUrl});
            }
            window.close();
        }

        if (document.readyState !== 'loading') {
            run();
        } else {
            document.addEventListener('DOMContentLoaded', function () {
                run();
            });
        }
    </script>
    </body>
    </html>
        """
    return HTMLResponse(content=html)

fastapi.openapi.docs.swagger_ui_default_parameters module-attribute

swagger_ui_default_parameters = {
    "dom_id": "#swagger-ui",
    "layout": "BaseLayout",
    "deepLinking": True,
    "showExtensions": True,
    "showCommonExtensions": True,
}

Default configurations for Swagger UI.

You can use it as a template to add any other configurations needed.