Configure Swagger UI¶
You can configure some extra Swagger UI parameters.
To configure them, pass the swagger_ui_parameters argument when creating the FastAPI() app object or to the get_swagger_ui_html() function.
swagger_ui_parameters receives a dictionary with the configurations passed to Swagger UI directly.
FastAPI converts the configurations to JSON to make them compatible with JavaScript, as that's what Swagger UI needs.
Disable Syntax Highlighting¶
For example, you could disable syntax highlighting in Swagger UI.
Without changing the settings, syntax highlighting is enabled by default:
But you can disable it by setting syntaxHighlight to False:
from fastapi import FastAPI
app = FastAPI(swagger_ui_parameters={"syntaxHighlight": False})
@app.get("/users/{username}")
async def read_user(username: str):
return {"message": f"Hello {username}"}
...and then Swagger UI won't show the syntax highlighting anymore:
Change the Theme¶
The same way you could set the syntax highlighting theme with the key "syntaxHighlight.theme" (notice that it has a dot in the middle):
from fastapi import FastAPI
app = FastAPI(swagger_ui_parameters={"syntaxHighlight.theme": "obsidian"})
@app.get("/users/{username}")
async def read_user(username: str):
return {"message": f"Hello {username}"}
That configuration would change the syntax highlighting color theme:
Change Default Swagger UI Parameters¶
FastAPI includes some default configuration parameters appropriate for most of the use cases.
It includes these default configurations:
# Code above omitted 👆
swagger_ui_default_parameters: Annotated[
Dict[str, Any],
Doc(
"""
Default configurations for Swagger UI.
You can use it as a template to add any other configurations needed.
"""
),
] = {
"dom_id": "#swagger-ui",
"layout": "BaseLayout",
"deepLinking": True,
"showExtensions": True,
"showCommonExtensions": True,
}
# Code below omitted 👇
👀 Full file preview
import json
from typing import Any, Dict, Optional
from fastapi.encoders import jsonable_encoder
from starlette.responses import HTMLResponse
from typing_extensions import Annotated, Doc
swagger_ui_default_parameters: Annotated[
Dict[str, Any],
Doc(
"""
Default configurations for Swagger UI.
You can use it as a template to add any other configurations needed.
"""
),
] = {
"dom_id": "#swagger-ui",
"layout": "BaseLayout",
"deepLinking": True,
"showExtensions": True,
"showCommonExtensions": True,
}
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/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/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)
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)
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)
You can override any of them by setting a different value in the argument swagger_ui_parameters.
For example, to disable deepLinking you could pass these settings to swagger_ui_parameters:
from fastapi import FastAPI
app = FastAPI(swagger_ui_parameters={"deepLinking": False})
@app.get("/users/{username}")
async def read_user(username: str):
return {"message": f"Hello {username}"}
Other Swagger UI Parameters¶
To see all the other possible configurations you can use, read the official docs for Swagger UI parameters.
JavaScript-only settings¶
Swagger UI also allows other configurations to be JavaScript-only objects (for example, JavaScript functions).
FastAPI also includes these JavaScript-only presets settings:
presets: [
SwaggerUIBundle.presets.apis,
SwaggerUIBundle.SwaggerUIStandalonePreset
]
These are JavaScript objects, not strings, so you can't pass them from Python code directly.
If you need to use JavaScript-only configurations like those, you can use one of the methods above. Override all the Swagger UI path operation and manually write any JavaScript you need.