diff --git a/frontend/src/App.vue b/frontend/src/App.vue
index 0decfba9..5a327688 100644
--- a/frontend/src/App.vue
+++ b/frontend/src/App.vue
@@ -1,12 +1,13 @@
 <script setup lang="ts">
 import { RouterView, useRouter, useRoute } from 'vue-router'
-import { onMounted } from 'vue'
+import { onMounted, watch } from 'vue'
 import Toast from '@/components/common/Toast.vue'
-import { getPublicSettings } from '@/api/auth'
+import { useAppStore } from '@/stores'
 import { getSetupStatus } from '@/api/setup'
 
 const router = useRouter()
 const route = useRoute()
+const appStore = useAppStore()
 
 /**
  * Update favicon dynamically
@@ -24,6 +25,19 @@ function updateFavicon(logoUrl: string) {
   link.href = logoUrl
 }
 
+// Watch for site settings changes and update favicon/title
+watch(() => appStore.siteLogo, (newLogo) => {
+  if (newLogo) {
+    updateFavicon(newLogo)
+  }
+}, { immediate: true })
+
+watch(() => appStore.siteName, (newName) => {
+  if (newName) {
+    document.title = `${newName} - AI API Gateway`
+  }
+}, { immediate: true })
+
 onMounted(async () => {
   // Check if setup is needed
   try {
@@ -36,21 +50,8 @@ onMounted(async () => {
     // If setup endpoint fails, assume normal mode and continue
   }
 
-  try {
-    const settings = await getPublicSettings()
-
-    // Update favicon if logo is set
-    if (settings.site_logo) {
-      updateFavicon(settings.site_logo)
-    }
-
-    // Update page title if site name is set
-    if (settings.site_name) {
-      document.title = `${settings.site_name} - AI API Gateway`
-    }
-  } catch (error) {
-    console.error('Failed to load public settings for favicon:', error)
-  }
+  // Load public settings into appStore (will be cached for other components)
+  await appStore.fetchPublicSettings()
 })
 </script>
 
diff --git a/frontend/src/components/layout/AppHeader.vue b/frontend/src/components/layout/AppHeader.vue
index 5593c8bb..a411f16b 100644
--- a/frontend/src/components/layout/AppHeader.vue
+++ b/frontend/src/components/layout/AppHeader.vue
@@ -156,7 +156,6 @@ import { ref, computed, onMounted, onBeforeUnmount } from 'vue';
 import { useRouter, useRoute } from 'vue-router';
 import { useI18n } from 'vue-i18n';
 import { useAppStore, useAuthStore } from '@/stores';
-import { authAPI } from '@/api';
 import LocaleSwitcher from '@/components/common/LocaleSwitcher.vue';
 import SubscriptionProgressMini from '@/components/common/SubscriptionProgressMini.vue';
 
@@ -169,7 +168,7 @@ const authStore = useAuthStore();
 const user = computed(() => authStore.user);
 const dropdownOpen = ref(false);
 const dropdownRef = ref<HTMLElement | null>(null);
-const contactInfo = ref('');
+const contactInfo = computed(() => appStore.contactInfo);
 
 const userInitials = computed(() => {
   if (!user.value) return '';
@@ -230,14 +229,8 @@ function handleClickOutside(event: MouseEvent) {
   }
 }
 
-onMounted(async () => {
+onMounted(() => {
   document.addEventListener('click', handleClickOutside);
-  try {
-    const settings = await authAPI.getPublicSettings();
-    contactInfo.value = settings.contact_info || '';
-  } catch (error) {
-    console.error('Failed to load contact info:', error);
-  }
 });
 
 onBeforeUnmount(() => {
diff --git a/frontend/src/components/layout/AppSidebar.vue b/frontend/src/components/layout/AppSidebar.vue
index 7d5cf341..5f89c717 100644
--- a/frontend/src/components/layout/AppSidebar.vue
+++ b/frontend/src/components/layout/AppSidebar.vue
@@ -131,11 +131,10 @@
 </template>
 
 <script setup lang="ts">
-import { computed, h, ref, onMounted } from 'vue';
+import { computed, h, ref } from 'vue';
 import { useRoute } from 'vue-router';
 import { useI18n } from 'vue-i18n';
 import { useAppStore, useAuthStore } from '@/stores';
-import { getPublicSettings } from '@/api/auth';
 import VersionBadge from '@/components/common/VersionBadge.vue';
 
 const { t } = useI18n();
@@ -149,21 +148,10 @@ const mobileOpen = computed(() => appStore.mobileOpen);
 const isAdmin = computed(() => authStore.isAdmin);
 const isDark = ref(document.documentElement.classList.contains('dark'));
 
-// Site settings
-const siteName = ref('Sub2API');
-const siteLogo = ref('');
-const siteVersion = ref('');
-
-onMounted(async () => {
-  try {
-    const settings = await getPublicSettings();
-    siteName.value = settings.site_name || 'Sub2API';
-    siteLogo.value = settings.site_logo || '';
-    siteVersion.value = settings.version || '';
-  } catch (error) {
-    console.error('Failed to load public settings:', error);
-  }
-});
+// Site settings from appStore (cached, no flicker)
+const siteName = computed(() => appStore.siteName);
+const siteLogo = computed(() => appStore.siteLogo);
+const siteVersion = computed(() => appStore.siteVersion);
 
 // SVG Icon Components
 const DashboardIcon = {
diff --git a/frontend/src/stores/app.ts b/frontend/src/stores/app.ts
index 1bf1a6f3..e3d76cff 100644
--- a/frontend/src/stores/app.ts
+++ b/frontend/src/stores/app.ts
@@ -5,8 +5,9 @@
 
 import { defineStore } from 'pinia';
 import { ref, computed } from 'vue';
-import type { Toast, ToastType } from '@/types';
+import type { Toast, ToastType, PublicSettings } from '@/types';
 import { checkUpdates as checkUpdatesAPI, type VersionInfo, type ReleaseInfo } from '@/api/admin/system';
+import { getPublicSettings as fetchPublicSettingsAPI } from '@/api/auth';
 
 export const useAppStore = defineStore('app', () => {
   // ==================== State ====================
@@ -16,6 +17,15 @@ export const useAppStore = defineStore('app', () => {
   const loading = ref<boolean>(false);
   const toasts = ref<Toast[]>([]);
 
+  // Public settings cache state
+  const publicSettingsLoaded = ref<boolean>(false);
+  const publicSettingsLoading = ref<boolean>(false);
+  const siteName = ref<string>('Sub2API');
+  const siteLogo = ref<string>('');
+  const siteVersion = ref<string>('');
+  const contactInfo = ref<string>('');
+  const apiBaseUrl = ref<string>('');
+
   // Version cache state
   const versionLoaded = ref<boolean>(false);
   const versionLoading = ref<boolean>(false);
@@ -268,6 +278,59 @@ export const useAppStore = defineStore('app', () => {
     hasUpdate.value = false;
   }
 
+  // ==================== Public Settings Management ====================
+
+  /**
+   * Fetch public settings (uses cache unless force=true)
+   * @param force - Force refresh from API
+   */
+  async function fetchPublicSettings(force = false): Promise<PublicSettings | null> {
+    // Return cached data if available and not forcing refresh
+    if (publicSettingsLoaded.value && !force) {
+      return {
+        registration_enabled: false,
+        email_verify_enabled: false,
+        turnstile_enabled: false,
+        turnstile_site_key: '',
+        site_name: siteName.value,
+        site_logo: siteLogo.value,
+        site_subtitle: '',
+        api_base_url: apiBaseUrl.value,
+        contact_info: contactInfo.value,
+        version: siteVersion.value,
+      };
+    }
+
+    // Prevent duplicate requests
+    if (publicSettingsLoading.value) {
+      return null;
+    }
+
+    publicSettingsLoading.value = true;
+    try {
+      const data = await fetchPublicSettingsAPI();
+      siteName.value = data.site_name || 'Sub2API';
+      siteLogo.value = data.site_logo || '';
+      siteVersion.value = data.version || '';
+      contactInfo.value = data.contact_info || '';
+      apiBaseUrl.value = data.api_base_url || '';
+      publicSettingsLoaded.value = true;
+      return data;
+    } catch (error) {
+      console.error('Failed to fetch public settings:', error);
+      return null;
+    } finally {
+      publicSettingsLoading.value = false;
+    }
+  }
+
+  /**
+   * Clear public settings cache
+   */
+  function clearPublicSettingsCache(): void {
+    publicSettingsLoaded.value = false;
+  }
+
   // ==================== Return Store API ====================
 
   return {
@@ -277,6 +340,14 @@ export const useAppStore = defineStore('app', () => {
     loading,
     toasts,
 
+    // Public settings state
+    publicSettingsLoaded,
+    siteName,
+    siteLogo,
+    siteVersion,
+    contactInfo,
+    apiBaseUrl,
+
     // Version state
     versionLoaded,
     versionLoading,
@@ -309,5 +380,9 @@ export const useAppStore = defineStore('app', () => {
     // Version actions
     fetchVersion,
     clearVersionCache,
+
+    // Public settings actions
+    fetchPublicSettings,
+    clearPublicSettingsCache,
   };
 });
diff --git a/frontend/src/views/admin/SettingsView.vue b/frontend/src/views/admin/SettingsView.vue
index eaff834d..5a70df61 100644
--- a/frontend/src/views/admin/SettingsView.vue
+++ b/frontend/src/views/admin/SettingsView.vue
@@ -499,6 +499,8 @@ async function saveSettings() {
   saving.value = true;
   try {
     await adminAPI.settings.updateSettings(form);
+    // Refresh cached public settings so sidebar/header update immediately
+    await appStore.fetchPublicSettings(true);
     appStore.showSuccess(t('admin.settings.settingsSaved'));
   } catch (error: any) {
     appStore.showError(t('admin.settings.failedToSave') + ': ' + (error.message || t('common.unknownError')));