diff --git a/api/src/app.ts b/api/src/app.ts
index 967776a..e6dfcf0 100644
--- a/api/src/app.ts
+++ b/api/src/app.ts
@@ -1,7 +1,7 @@
 import { resolve } from 'node:path'
 import express from 'express'
 import { errorHandler, createSiteMiddleware, createSpaMiddleware } from '@data-fair/lib-express'
-import config, { uiConfig } from '#config'
+import config, { uiConfig, siteResourcesHtml } from '#config'
 import adminRouter from './admin/router.ts'
 
 export const app = express()
@@ -16,7 +16,10 @@ app.use(express.urlencoded({ extended: true }))
 app.use('/api/admin', adminRouter)
 
 if (config.serveUi) {
-  app.use(await createSpaMiddleware(resolve(import.meta.dirname, '../../ui/dist'), uiConfig))
+  app.use(await createSpaMiddleware(resolve(import.meta.dirname, '../../ui/dist'), uiConfig, {
+    extraHtmlTemplateParams: { SITE_RESOURCES: siteResourcesHtml },
+    privateDirectoryUrl: config.useSimpleDirectory ? config.privateDirectoryUrl : undefined
+  }))
 }
 
 app.use(errorHandler)
diff --git a/api/src/config.ts b/api/src/config.ts
index cc95e4f..4edf3df 100644
--- a/api/src/config.ts
+++ b/api/src/config.ts
@@ -14,3 +14,10 @@ export const uiConfig = {
   useSimpleDirectory: apiConfig.useSimpleDirectory
 }
 export type UiConfig = typeof uiConfig
+
+// site theme and public info served by simple-directory, absent in standalone mode
+// the hash placeholders are filled by createSpaMiddleware (privateDirectoryUrl option)
+export const siteResourcesHtml = apiConfig.useSimpleDirectory
+  ? `<link href="{SITE_PATH}/simple-directory/api/sites/{THEME_CSS_HASH}_theme.css" rel="stylesheet">
+    <script src="{SITE_PATH}/simple-directory/api/sites/{PUBLIC_SITE_INFO_HASH}_public.js"></script>`
+  : ''
diff --git a/ui/index.html b/ui/index.html
index 38faf6f..bd29ac2 100644
--- a/ui/index.html
+++ b/ui/index.html
@@ -3,7 +3,7 @@
   <head>
     <meta charset="UTF-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
-    <link href="{SITE_PATH}/simple-directory/api/sites/_theme.css" rel="stylesheet">
+    {SITE_RESOURCES}
   </head>
   <body>
     <div id="app"></div>
diff --git a/ui/src/components/home.vue b/ui/src/components/home.vue
index e05f34a..ab0d627 100644
--- a/ui/src/components/home.vue
+++ b/ui/src/components/home.vue
@@ -208,10 +208,10 @@ marked.setOptions({
   gfm: true
 })
 
-const { info, externalDocs, servers, schemas } = defineProps<{
+const { info, externalDocs = undefined, servers = undefined, schemas } = defineProps<{
   info: OpenAPISpecs['info'],
-  externalDocs: OpenAPISpecs['externalDocs'],
-  servers: OpenAPISpecs['servers'],
+  externalDocs?: OpenAPISpecs['externalDocs'],
+  servers?: OpenAPISpecs['servers'],
   schemas: Components['schemas'] | undefined
 }>()
 
diff --git a/ui/src/main.ts b/ui/src/main.ts
index 0708b5f..4c72c0b 100644
--- a/ui/src/main.ts
+++ b/ui/src/main.ts
@@ -26,7 +26,7 @@ import DOMPurify from 'dompurify'
 
   let session, localeDayjs, i18n
   if ($uiConfig.useSimpleDirectory) { // Don't integrate session in standalone mode
-    session = await createSession({ directoryUrl: $sitePath + '/simple-directory', siteInfo: true })
+    session = await createSession({ directoryUrl: $sitePath + '/simple-directory' })
     localeDayjs = createLocaleDayjs(session.state.lang)
     i18n = createI18n({ locale: session.state.lang })
     Object.assign(vuetifyOptions, vuetifySessionOptions(session))
diff --git a/ui/src/pages/index.vue b/ui/src/pages/index.vue
index 9be5d80..65a3354 100644
--- a/ui/src/pages/index.vue
+++ b/ui/src/pages/index.vue
@@ -141,15 +141,15 @@ const fullOperation = computed<{
   return null
 })
 
-watch(route.query, () => {
-  derefDoc.value = undefined
-  errorMessage.value = null
-
+/*
+ * Resolve the doc URL from the query
+ * -> watched by value, so that operation/params changes in the query do not refetch the doc
+ */
+const target = computed<{ url?: string, error?: string }>(() => {
   if (route.query.urlType) {
     // Check url type
     if (!Object.keys($uiConfig.allowedUrls).includes(route.query.urlType as string)) {
-      errorMessage.value = t('errors.invalidUrlType')
-      return
+      return { error: t('errors.invalidUrlType') }
     }
 
     const template = $uiConfig.allowedUrls[route.query.urlType as string]
@@ -159,18 +159,24 @@ watch(route.query, () => {
     const requiredParams = (template.match(/{[^}]+}/g) || []).map((param) => param.slice(1, -1))
     const missingParams = requiredParams.filter((param) => !queryParams[param])
     if (missingParams.length > 0) {
-      errorMessage.value = t('errors.missingParams', { params: missingParams.join(', ') })
-      return
+      return { error: t('errors.missingParams', { params: missingParams.join(', ') }) }
     }
 
     // Replace the template params with the query params
-    url.value = urlTemplate.parseTemplate(template).expand(queryParams)
+    return { url: urlTemplate.parseTemplate(template).expand(queryParams) }
   } else if ($uiConfig.defaultUrl) {
-    url.value = $uiConfig.defaultUrl
+    return { url: $uiConfig.defaultUrl }
   } else {
-    errorMessage.value = t('errors.missingUrl')
+    return { error: t('errors.missingUrl') }
   }
+})
+
+watch([() => target.value.url, () => target.value.error], ([newUrl, error]) => {
+  derefDoc.value = undefined
+  errorMessage.value = error ?? null
+  if (!newUrl) return
 
+  url.value = newUrl
   urlFetch.refresh()
 }, { immediate: true })
 
diff --git a/ui/vite.config.ts b/ui/vite.config.ts
index 52c3963..3c1d341 100644
--- a/ui/vite.config.ts
+++ b/ui/vite.config.ts
@@ -70,8 +70,8 @@ export default defineConfig(({ command }) => ({
       async transformIndexHtml (html) {
         // in production this injection will be performed by an express middleware
         if (process.env.NODE_ENV !== 'development') return html
-        const { uiConfig } = await import('../api/src/config.ts')
-        return microTemplate(html, { SITE_PATH: '', UI_CONFIG: JSON.stringify(uiConfig) })
+        const { uiConfig, siteResourcesHtml } = await import('../api/src/config.ts')
+        return microTemplate(html, { SITE_RESOURCES: siteResourcesHtml, SITE_PATH: '', UI_CONFIG: JSON.stringify(uiConfig), THEME_CSS_HASH: '', PUBLIC_SITE_INFO_HASH: '' })
       }
     }
   ],