cipherunits · ehs22n · Sep 1, 2026 · Sep 1, 2026
diff --git a/bindings/csharp/FusionFramework/Swagger.cs b/bindings/csharp/FusionFramework/Swagger.cs
@@ -392,18 +392,22 @@ static string UiHtml(SwaggerConfig swagger, string openapiUrl, string? primaryNa
             : "null";
         var title = JsonSerializer.Serialize(swagger.PageTitle).Trim('"');
         var navbarEnabled = swagger.NavbarEnabled;
+        var versionUrls = swagger.Urls?.Count > 0;
+        var needsStandalone = navbarEnabled || versionUrls;
         var hideUrlCss = navbarEnabled && !swagger.ShowUrlInput
             ? """
     <style>
-      .swagger-ui .topbar .download-url-input,
-      .swagger-ui .topbar .download-url-button { display: none !important; }
+      .swagger-ui .topbar .download-url-wrapper input[type=text],
+      .swagger-ui .topbar .download-url-wrapper .download-url-button {
+        display: none !important;
+      }
     </style>
 """
             : "";
-        var standalone = navbarEnabled
+        var standalone = needsStandalone && File.Exists(Path.Combine(AssetsDirectory(), "swagger-ui-standalone-preset.js"))
             ? $"""<script src="{AssetUrl(swagger.Path, "swagger-ui-standalone-preset.js")}"></script>"""
             : "";
-        var navbarJs = navbarEnabled ? "true" : "false";
+        var navbarJs = needsStandalone ? "true" : "false";
 
         return $$"""
 <!doctype html>

diff --git a/crates/fusion-node/index.js b/crates/fusion-node/index.js
@@ -956,6 +956,8 @@ function swaggerUiHtml(swagger, openapiUrl, primaryName = null) {
 
   const navbarEnabled = !!swagger.navbar?.enabled
   const showUrlInput = swagger.navbar?.showUrlInput !== false
+  const versionUrls = swagger.navbar?.urls?.length > 0
+  const needsStandalone = navbarEnabled || versionUrls
   const hideUrlCss =
     navbarEnabled && !showUrlInput
       ? `<style>
@@ -965,9 +967,10 @@ function swaggerUiHtml(swagger, openapiUrl, primaryName = null) {
       }
     </style>`
       : ''
-  const standaloneScript = navbarEnabled
-    ? `<script src="${swaggerAssetUrl(swagger.path, 'swagger-ui-standalone-preset.js')}"></script>`
-    : ''
+  const standaloneScript =
+    needsStandalone && SWAGGER_ASSETS['swagger-ui-standalone-preset.js']
+      ? `<script src="${swaggerAssetUrl(swagger.path, 'swagger-ui-standalone-preset.js')}"></script>`
+      : ''
 
   return `<!doctype html>
 <html>
@@ -987,7 +990,7 @@ function swaggerUiHtml(swagger, openapiUrl, primaryName = null) {
         var opts = ${uiJson};
         opts.presets = [SwaggerUIBundle.presets.apis];
         opts.plugins = [SwaggerUIBundle.plugins.DownloadUrl];
-        if (${navbarEnabled ? 'true' : 'false'} && typeof SwaggerUIStandalonePreset !== 'undefined') {
+        if (${needsStandalone ? 'true' : 'false'} && typeof SwaggerUIStandalonePreset !== 'undefined') {
           opts.presets.push(SwaggerUIStandalonePreset);
           opts.layout = 'StandaloneLayout';
         } else {

diff --git a/crates/fusion-py/python/fusion_framework/app.py b/crates/fusion-py/python/fusion_framework/app.py
@@ -257,17 +257,21 @@ def _swagger_ui_html(swagger: dict[str, Any], openapi_url: str, primary_name: st
 
     navbar_enabled = bool(navbar.get("enabled"))
     show_url_input = bool(navbar.get("showUrlInput", True))
+    version_urls = navbar.get("urls") or []
+    needs_standalone = navbar_enabled or bool(version_urls)
     hide_url_css = ""
     if navbar_enabled and not show_url_input:
         # Keep the version <select>; hide only the free-text Explore box + button.
         hide_url_css = """
     <style>
-      .swagger-ui .topbar .download-url-input,
-      .swagger-ui .topbar .download-url-button { display: none !important; }
+      .swagger-ui .topbar .download-url-wrapper input[type=text],
+      .swagger-ui .topbar .download-url-wrapper .download-url-button {
+        display: none !important;
+      }
     </style>"""
 
     standalone_script = ""
-    if navbar_enabled:
+    if needs_standalone and "swagger-ui-standalone-preset.js" in _SWAGGER_ASSETS:
         standalone_script = (
             f'<script src="{_swagger_asset_url(prefix, "swagger-ui-standalone-preset.js")}"></script>'
         )
@@ -277,7 +281,7 @@ def _swagger_ui_html(swagger: dict[str, Any], openapi_url: str, primary_name: st
         var opts = {ui_json};
         opts.presets = [SwaggerUIBundle.presets.apis];
         opts.plugins = [SwaggerUIBundle.plugins.DownloadUrl];
-        if ({str(navbar_enabled).lower()} && typeof SwaggerUIStandalonePreset !== 'undefined') {{
+        if ({str(needs_standalone).lower()} && typeof SwaggerUIStandalonePreset !== 'undefined') {{
           opts.presets.push(SwaggerUIStandalonePreset);
           opts.layout = 'StandaloneLayout';
         }} else {{

diff --git a/crates/fusion-py/python/fusion_framework/test_swagger.py b/crates/fusion-py/python/fusion_framework/test_swagger.py
@@ -2,7 +2,14 @@
 
 from fusion_framework._fusion import has_unversioned_routes, openapi_spec, route_versions
 from fusion_framework.api import FusionBaseApi
-from fusion_framework.app import UNVERSIONED_SWAGGER_NAME, _swagger_version_urls
+from fusion_framework.app import (
+    UNVERSIONED_SWAGGER_NAME,
+    _apply_version_navbar,
+    _swagger_settings,
+    _swagger_ui_html,
+    _swagger_version_urls,
+)
+from fusion_framework.config import Settings
 from fusion_framework.route import clear_registry, route
 
 
@@ -83,3 +90,28 @@ def get(self):
         {"url": "/swagger/v2/openapi.json", "name": "v2"},
         {"url": "/swagger/default/openapi.json", "name": "default"},
     ]
+
+
+def test_swagger_ui_html_version_navbar():
+    @route("/hello", version="v1")
+    class V1Hello(FusionBaseApi):
+        def get(self):
+            return {"v": 1}
+
+    @route("/hello", version="v2")
+    class V2Hello(FusionBaseApi):
+        def get(self):
+            return {"v": 2}
+
+    swagger = _swagger_settings(Settings())
+    labels = _apply_version_navbar(swagger)
+    assert labels == ["v1", "v2"]
+
+    html = _swagger_ui_html(swagger, "/swagger/openapi.json", primary_name="v1")
+    assert "/swagger/v1/openapi.json" in html
+    assert "/swagger/v2/openapi.json" in html
+    assert '"urls"' in html
+    assert "StandaloneLayout" in html
+    assert "swagger-ui-standalone-preset.js" in html
+    assert ".download-url-wrapper input[type=text]" in html
+    assert ".download-url-input" not in html