diff --git a/src/App.tsx b/src/App.tsx
index 41c6028..3b82754 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -47,7 +47,7 @@ import { AccessManagementHub, AdminMandatesPage, AdminUsersPage, AdminUserMandat
 import { PromptsPage, FilesPage, ConnectionsPage } from './pages/basedata';
 
 // Billing Pages
-import { BillingDashboard, BillingTransactions, BillingAdmin } from './pages/billing';
+import { BillingDashboard, BillingDataView, BillingAdmin } from './pages/billing';
 
 function App() {
     // Load saved theme preference and set app name on app mount
@@ -117,8 +117,8 @@ function App() {
                             {/* BILLING ROUTES                                 */}
                             {/* ============================================== */}
                             <Route path="billing">
-                                <Route index element={<BillingDashboard />} />
-                                <Route path="transactions" element={<BillingTransactions />} />
+                                <Route index element={<Navigate to="/billing/transactions" replace />} />
+                                <Route path="transactions" element={<BillingDataView />} />
                             </Route>
                             
                             {/* ============================================== */}
diff --git a/src/api/billingApi.ts b/src/api/billingApi.ts
index 800adf1..69ebf34 100644
--- a/src/api/billingApi.ts
+++ b/src/api/billingApi.ts
@@ -39,6 +39,8 @@ export interface BillingTransaction {
   featureCode?: string;
   aicoreProvider?: string;
   createdAt?: string;
+  mandateId?: string;
+  mandateName?: string;
 }
 
 export interface BillingSettings {
@@ -277,3 +279,95 @@ export async function fetchUsersForMandateAdmin(
     method: 'get'
   });
 }
+
+// ============================================================================
+// MANDATE VIEW TYPES & API FUNCTIONS
+// ============================================================================
+
+export interface MandateBalance {
+  mandateId: string;
+  mandateName: string;
+  billingModel: BillingModel;
+  totalBalance: number;
+  userCount: number;
+  defaultUserCredit: number;
+  warningThresholdPercent: number;
+  blockOnZeroBalance: boolean;
+}
+
+/**
+ * Fetch mandate-level balances (SysAdmin only)
+ * Endpoint: GET /api/billing/view/mandates/balances
+ */
+export async function fetchMandateViewBalances(
+  request: ApiRequestFunction
+): Promise<MandateBalance[]> {
+  return await request({
+    url: '/api/billing/view/mandates/balances',
+    method: 'get'
+  });
+}
+
+/**
+ * Fetch mandate-level transactions (SysAdmin only)
+ * Endpoint: GET /api/billing/view/mandates/transactions
+ */
+export async function fetchMandateViewTransactions(
+  request: ApiRequestFunction,
+  limit: number = 100
+): Promise<BillingTransaction[]> {
+  return await request({
+    url: '/api/billing/view/mandates/transactions',
+    method: 'get',
+    params: { limit }
+  });
+}
+
+// ============================================================================
+// USER VIEW TYPES & API FUNCTIONS
+// ============================================================================
+
+export interface UserBalance {
+  accountId: string;
+  mandateId: string;
+  mandateName: string;
+  userId: string;
+  userName: string;
+  balance: number;
+  warningThreshold: number;
+  isWarning: boolean;
+  enabled: boolean;
+}
+
+export interface UserTransaction extends BillingTransaction {
+  userId?: string;
+  userName?: string;
+}
+
+/**
+ * Fetch user-level balances (RBAC-based)
+ * Endpoint: GET /api/billing/view/users/balances
+ */
+export async function fetchUserViewBalances(
+  request: ApiRequestFunction
+): Promise<UserBalance[]> {
+  return await request({
+    url: '/api/billing/view/users/balances',
+    method: 'get'
+  });
+}
+
+/**
+ * Fetch user-level transactions (RBAC-based)
+ * Endpoint: GET /api/billing/view/users/transactions
+ */
+export async function fetchUserViewTransactions(
+  request: ApiRequestFunction,
+  limit: number = 100
+): Promise<UserTransaction[]> {
+  return await request({
+    url: '/api/billing/view/users/transactions',
+    method: 'get',
+    params: { limit }
+  });
+}
diff --git a/src/components/FormGenerator/FormGeneratorTable/FormGeneratorTable.module.css b/src/components/FormGenerator/FormGeneratorTable/FormGeneratorTable.module.css
index fa439f6..1195f68 100644
--- a/src/components/FormGenerator/FormGeneratorTable/FormGeneratorTable.module.css
+++ b/src/components/FormGenerator/FormGeneratorTable/FormGeneratorTable.module.css
@@ -7,7 +7,11 @@
   /* Fill available space and constrain height */
   min-height: 0;
   flex: 1;
-  /* No overflow - children handle their own scrolling */
+  /* Prevent overflow - constrain to parent height */
+  overflow: hidden;
+  /* Ensure container respects parent's height */
+  height: 100%;
+  max-height: 100%;
 }
 
 .title {
@@ -18,18 +22,46 @@
   margin-bottom: 10px;
 }
 
-/* Table Container - scrollable area for table data only */
-.tableContainer {
-  position: relative;
-  overflow: auto;
+/* Table wrapper - contains top scrollbar and table container */
+.tableWrapper {
+  display: flex;
+  flex-direction: column;
+  flex: 1;
+  min-height: 0;
+  /* Constrain height to prevent growing beyond parent */
+  max-height: 100%;
+  overflow: hidden;
   border: 1px solid var(--color-primary);
   border-radius: 25px;
   background: var(--color-bg);
-  /* Fill remaining space after controls */
-  flex: 1;
+}
+
+/* Top horizontal scrollbar - syncs with table container */
+.topScrollbar {
+  overflow-x: auto;
+  overflow-y: hidden;
+  flex-shrink: 0;
+  background: var(--color-bg);
+  border-bottom: 1px solid var(--color-primary);
+  border-radius: 25px 25px 0 0;
+}
+
+/* Inner div that matches table width for proper scrollbar sizing */
+.topScrollbarInner {
+  height: 1px; /* Minimal height - just need width to activate scrollbar */
+}
+
+/* Table Container - scrollable area for table data only (vertical only) */
+.tableContainer {
+  position: relative;
+  overflow-x: hidden; /* Horizontal scroll handled by topScrollbar */
+  overflow-y: auto;
+  background: var(--color-bg);
+  /* Fill remaining space but constrain to available height */
+  flex: 1 1 0;
   min-height: 0;
-  /* Clip content to border-radius but allow sticky to work */
-  isolation: isolate;
+  max-height: 100%;
+  border-radius: 0 0 25px 25px;
 }
 
 /* Empty table styling - no extra space, just header */
@@ -39,6 +71,11 @@
   max-height: none;
 }
 
+/* Hide top scrollbar when table is empty */
+.emptyTable .topScrollbar {
+  display: none;
+}
+
 /* Empty state styling */
 .emptyState {
   display: flex;
@@ -734,7 +771,7 @@ tbody .actionsColumn {
   outline: none;
 }
 
-/* Custom scrollbar for table container */
+/* Custom scrollbar for table container (vertical only) */
 .tableContainer::-webkit-scrollbar {
   width: 8px;
   height: 8px;
@@ -754,6 +791,25 @@ tbody .actionsColumn {
   background: var(--color-secondary);
 }
 
+/* Custom scrollbar for top scrollbar (horizontal only) */
+.topScrollbar::-webkit-scrollbar {
+  height: 8px;
+}
+
+.topScrollbar::-webkit-scrollbar-track {
+  background: var(--color-gray-disabled);
+  border-radius: 4px;
+}
+
+.topScrollbar::-webkit-scrollbar-thumb {
+  background: var(--color-gray);
+  border-radius: 4px;
+}
+
+.topScrollbar::-webkit-scrollbar-thumb:hover {
+  background: var(--color-secondary);
+}
+
 /* Loading State */
 .loadingState {
   display: flex;
diff --git a/src/components/FormGenerator/FormGeneratorTable/FormGeneratorTable.tsx b/src/components/FormGenerator/FormGeneratorTable/FormGeneratorTable.tsx
index 936231f..c54cfa0 100644
--- a/src/components/FormGenerator/FormGeneratorTable/FormGeneratorTable.tsx
+++ b/src/components/FormGenerator/FormGeneratorTable/FormGeneratorTable.tsx
@@ -338,6 +338,11 @@ export function FormGeneratorTable<T extends Record<string, any>>({
   const tableRef = useRef<HTMLTableElement>(null);
   const tableContainerRef = useRef<HTMLDivElement>(null);
   
+  // Refs for top scrollbar synchronization
+  const topScrollbarRef = useRef<HTMLDivElement>(null);
+  const topScrollbarInnerRef = useRef<HTMLDivElement>(null);
+  const isScrollingSyncRef = useRef<boolean>(false); // Prevent scroll sync loops
+  
   // Track container width for actions column 20% threshold
   const [containerWidth, setContainerWidth] = useState<number>(0);
   
@@ -945,6 +950,53 @@ export function FormGeneratorTable<T extends Record<string, any>>({
     };
   }, []);
 
+  // Sync top scrollbar width with table width and handle scroll synchronization
+  useEffect(() => {
+    const tableContainer = tableContainerRef.current;
+    const topScrollbar = topScrollbarRef.current;
+    const topScrollbarInner = topScrollbarInnerRef.current;
+    const table = tableRef.current;
+    
+    if (!tableContainer || !topScrollbar || !topScrollbarInner || !table) return;
+    
+    // Update top scrollbar inner width to match table width
+    const updateScrollbarWidth = () => {
+      const tableWidth = table.scrollWidth;
+      topScrollbarInner.style.width = `${tableWidth}px`;
+    };
+    
+    // Initial width calculation
+    updateScrollbarWidth();
+    
+    // Observe table size changes
+    const resizeObserver = new ResizeObserver(updateScrollbarWidth);
+    resizeObserver.observe(table);
+    
+    // Sync scroll positions
+    const syncTopToContainer = () => {
+      if (isScrollingSyncRef.current) return;
+      isScrollingSyncRef.current = true;
+      tableContainer.scrollLeft = topScrollbar.scrollLeft;
+      requestAnimationFrame(() => { isScrollingSyncRef.current = false; });
+    };
+    
+    const syncContainerToTop = () => {
+      if (isScrollingSyncRef.current) return;
+      isScrollingSyncRef.current = true;
+      topScrollbar.scrollLeft = tableContainer.scrollLeft;
+      requestAnimationFrame(() => { isScrollingSyncRef.current = false; });
+    };
+    
+    topScrollbar.addEventListener('scroll', syncTopToContainer);
+    tableContainer.addEventListener('scroll', syncContainerToTop);
+    
+    return () => {
+      resizeObserver.disconnect();
+      topScrollbar.removeEventListener('scroll', syncTopToContainer);
+      tableContainer.removeEventListener('scroll', syncContainerToTop);
+    };
+  }, [displayData, detectedColumns, columnWidths]); // Re-run when data or columns change
+
   // Track which cells are currently being updated (for loading state)
   const [updatingCells, setUpdatingCells] = useState<Set<string>>(new Set());
 
@@ -1367,26 +1419,36 @@ export function FormGeneratorTable<T extends Record<string, any>>({
         />
       )}
 
-      {/* Table */}
-      <div 
-        ref={tableContainerRef}
-        className={`${styles.tableContainer} ${displayData.length === 0 && !loading ? styles.emptyTable : ''}`}
-      >
-        {/* Loading overlay - shown while loading */}
-        {loading && (
-          <div className={styles.loadingOverlay}>
-            <div className={styles.loadingSpinner}></div>
-            <p>{t('common.loading', 'Loading...')}</p>
-          </div>
-        )}
+      {/* Table Wrapper - contains top scrollbar and table container */}
+      <div className={`${styles.tableWrapper} ${displayData.length === 0 && !loading ? styles.emptyTable : ''}`}>
+        {/* Top horizontal scrollbar - syncs with table container */}
+        <div 
+          ref={topScrollbarRef}
+          className={styles.topScrollbar}
+        >
+          <div ref={topScrollbarInnerRef} className={styles.topScrollbarInner} />
+        </div>
         
-        {/* Empty state - only shown when not loading AND no data */}
-        {!loading && displayData.length === 0 ? (
-          <div className={styles.emptyState}>
-            <p className={styles.emptyMessage}>{emptyMessage || t('formgen.empty', 'No data available')}</p>
-          </div>
-        ) : (
-          <table ref={tableRef} className={styles.table}>
+        {/* Table Container - vertical scroll only */}
+        <div 
+          ref={tableContainerRef}
+          className={styles.tableContainer}
+        >
+          {/* Loading overlay - shown while loading */}
+          {loading && (
+            <div className={styles.loadingOverlay}>
+              <div className={styles.loadingSpinner}></div>
+              <p>{t('common.loading', 'Loading...')}</p>
+            </div>
+          )}
+          
+          {/* Empty state - only shown when not loading AND no data */}
+          {!loading && displayData.length === 0 ? (
+            <div className={styles.emptyState}>
+              <p className={styles.emptyMessage}>{emptyMessage || t('formgen.empty', 'No data available')}</p>
+            </div>
+          ) : (
+            <table ref={tableRef} className={styles.table}>
             <thead>
               <tr>
                 {selectable && (
@@ -1704,7 +1766,8 @@ export function FormGeneratorTable<T extends Record<string, any>>({
               </tbody>
             )}
           </table>
-        )}
+          )}
+        </div>
       </div>
     </div>
   );
diff --git a/src/components/Navigation/MandateNavigation.tsx b/src/components/Navigation/MandateNavigation.tsx
index 85f5398..c67b0e0 100644
--- a/src/components/Navigation/MandateNavigation.tsx
+++ b/src/components/Navigation/MandateNavigation.tsx
@@ -8,16 +8,16 @@
  * Backend liefert Blocks-Struktur mit Static und Dynamic Blocks.
  * UI mappt uiComponent zu Icons via pageRegistry.
  * 
- * Struktur (gemäss Navigation-API-Konzept):
- * - SYSTEM (static block, order: 10)
- * - MEINE FEATURES (dynamic block, order: 15)
- *   - Mandant 1
- *     - Feature A
- *       - Instanz 1 (mit Views)
- * - WORKFLOWS (static block, order: 20)
- * - BASISDATEN (static block, order: 30)
- * - MIGRATE TO FEATURES (static block, order: 40)
- * - ADMINISTRATION (static block, order: 200)
+ * FLAT STRUCTURE (kompakte Darstellung):
+ * - SYSTEM (static block)
+ * - Mandant 1
+ *   - 🎯 Instanz 1 (Feature-Icon + Instanz-Name)
+ *   - 💼 Instanz 2 (Feature-Icon + Instanz-Name)
+ * - BASISDATEN (static block)
+ * - ADMINISTRATION (static block)
+ * 
+ * Jede Instanz zeigt das Icon des zugehörigen Features.
+ * Keine Gruppierung nach Features - direkt Instanzen unter Mandant.
  */
 
 import React, { useMemo } from 'react';
@@ -75,58 +75,52 @@ function featureViewToTreeNode(view: FeatureView): TreeNodeItem {
 }
 
 /**
- * Convert a FeatureInstance to TreeNodeItem
- * Instance node gets path to first view so clicking the instance name (e.g. PEK) navigates to dashboard.
+ * Convert a FeatureInstance to TreeNodeItem (with feature icon)
+ * Instance node gets path to first view so clicking the instance name navigates to dashboard.
+ * Shows the feature icon next to the instance name for visual distinction.
  */
-function featureInstanceToTreeNode(instance: FeatureInstance): TreeNodeItem {
+function featureInstanceToTreeNode(instance: FeatureInstance, featureUiComponent: string): TreeNodeItem {
   const children = instance.views.map(featureViewToTreeNode);
   return {
     id: instance.id,
     label: instance.uiLabel,
+    icon: getPageIcon(featureUiComponent), // Use feature icon for instance
     path: instance.views.length > 0 ? instance.views[0].uiPath : undefined,
     children,
     defaultExpanded: false,
   };
 }
 
-/**
- * Convert a MandateFeature to TreeNodeItem
- */
-function mandateFeatureToTreeNode(feature: MandateFeature): TreeNodeItem | null {
-  if (feature.instances.length === 0) {
-    return null;
-  }
-  
-  return {
-    id: feature.uiComponent,
-    label: feature.uiLabel,
-    icon: getPageIcon(feature.uiComponent),
-    badge: feature.instances.length,
-    children: feature.instances.map(featureInstanceToTreeNode),
-    defaultExpanded: false,
-  };
-}
-
 /**
  * Convert a NavigationMandate to TreeNodeItem
+ * 
+ * FLAT STRUCTURE: Instances are listed directly under mandate (no feature grouping).
+ * Each instance shows the feature's icon for visual distinction.
+ * 
+ * Before: Mandate → Feature → Instance → Views
+ * Now:    Mandate → Instance (with feature icon) → Views
  */
 function navigationMandateToTreeNode(mandate: NavigationMandate): TreeNodeItem | null {
   if (mandate.features.length === 0) {
     return null;
   }
   
-  const children = mandate.features
-    .map(mandateFeatureToTreeNode)
-    .filter((node): node is TreeNodeItem => node !== null);
+  // Flatten: collect all instances from all features directly under mandate
+  const instanceNodes: TreeNodeItem[] = [];
+  for (const feature of mandate.features) {
+    for (const instance of feature.instances) {
+      instanceNodes.push(featureInstanceToTreeNode(instance, feature.uiComponent));
+    }
+  }
   
-  if (children.length === 0) {
+  if (instanceNodes.length === 0) {
     return null;
   }
   
   return {
     id: mandate.id,
     label: mandate.uiLabel,
-    children,
+    children: instanceNodes,
     defaultExpanded: true,
   };
 }
diff --git a/src/components/Navigation/UserSection.tsx b/src/components/Navigation/UserSection.tsx
index 1d7ba38..e19cd0e 100644
--- a/src/components/Navigation/UserSection.tsx
+++ b/src/components/Navigation/UserSection.tsx
@@ -35,7 +35,7 @@ export const UserSection: React.FC = () => {
   };
   
   const handleBilling = () => {
-    navigate('/billing');
+    navigate('/billing/transactions');
     setShowMenu(false);
   };
   
diff --git a/src/components/ProviderSelector/ProviderSelector.module.css b/src/components/ProviderSelector/ProviderSelector.module.css
index 242df68..ddfa9c9 100644
--- a/src/components/ProviderSelector/ProviderSelector.module.css
+++ b/src/components/ProviderSelector/ProviderSelector.module.css
@@ -42,133 +42,90 @@
    ============================================================================ */
 
 .providerMultiSelect {
-  display: flex;
-  flex-direction: column;
-  gap: var(--spacing-xs, 4px);
   position: relative;
+  display: inline-block;
 }
 
-.providerMultiSelect.collapsed {
-  /* Collapsed state styles */
-}
-
-.providerMultiSelect.expanded {
-  /* Expanded state styles */
-}
-
-/* Collapsible Header Button */
-.collapseHeader {
+/* Trigger Button - matches iconButton style from PlaygroundPage */
+.triggerButton {
   display: flex;
   align-items: center;
-  gap: var(--spacing-xs, 4px);
-  padding: var(--spacing-xs, 4px) var(--spacing-sm, 8px);
-  border: 1px solid var(--color-border);
-  border-radius: var(--border-radius-md, 6px);
-  background: var(--color-bg-input);
-  color: var(--color-text-primary);
-  font-size: var(--font-size-sm, 0.875rem);
+  justify-content: center;
+  width: 36px;
+  height: 36px;
+  border: 1px solid var(--border-color, #3a3a3a);
+  border-radius: 6px;
+  background: var(--surface-color, #2d2d2d);
+  color: var(--text-secondary, #888);
   cursor: pointer;
-  transition: all 0.2s ease;
-  min-width: 140px;
+  transition: all 0.2s;
 }
 
-.collapseHeader:hover:not(:disabled) {
-  border-color: var(--color-primary);
-  background: var(--color-bg-hover);
+.triggerButton:hover:not(:disabled) {
+  background: var(--bg-secondary, #3a3a3a);
+  color: var(--text-primary, #fff);
 }
 
-.collapseHeader:disabled {
-  opacity: 0.6;
+.triggerButton:disabled {
+  opacity: 0.5;
   cursor: not-allowed;
 }
 
-.summaryIcons {
-  font-size: 0.9em;
+.buttonIcon {
+  font-size: 1.1rem;
 }
 
-.summaryText {
-  flex: 1;
-  text-align: left;
-  white-space: nowrap;
-  overflow: hidden;
-  text-overflow: ellipsis;
-}
-
-.expandIcon {
-  font-size: 0.7em;
-  color: var(--color-text-secondary);
-}
-
-/* Expandable Content - opens upward */
-.expandableContent {
+/* Dropdown Content - opens upward */
+.dropdownContent {
   position: absolute;
-  bottom: 100%;
-  left: 0;
-  right: 0;
-  z-index: 100;
-  margin-bottom: var(--spacing-xs, 4px);
-  padding: var(--spacing-sm, 8px);
-  background: #2d2d2d;
-  color: #e0e0e0;
-  border: 1px solid #444;
-  border-radius: var(--border-radius-md, 6px);
-  box-shadow: 0 -4px 12px rgba(0, 0, 0, 0.4);
-  min-width: 200px;
+  bottom: calc(100% + 4px);
+  left: 50%;
+  transform: translateX(-50%);
+  z-index: 1000;
+  padding: 8px;
+  background: var(--surface-color, #2d2d2d);
+  border: 1px solid var(--border-color, #3a3a3a);
+  border-radius: 6px;
+  box-shadow: 0 -4px 16px rgba(0, 0, 0, 0.5);
+  min-width: 220px;
 }
 
-.expandableContent .label {
-  color: #b0b0b0;
-}
-
-.expandableContent .checkboxList {
-  background: #252525;
-}
-
-.expandableContent .checkboxItem {
-  color: #e0e0e0;
-}
-
-.expandableContent .checkboxItem:hover {
-  background: #3a3a3a;
-}
-
-.expandableContent .providerName {
-  color: #e0e0e0;
-}
-
-.expandableContent .hint {
-  color: #888;
-}
-
-.expandableContent .actionButton {
-  background: #3a3a3a;
-  color: #e0e0e0;
-  border-color: #555;
-}
-
-.expandableContent .actionButton:hover:not(:disabled) {
-  background: #4a4a4a;
+.dropdownHeader {
+  font-size: 0.75rem;
+  font-weight: 500;
+  color: var(--text-secondary, #888);
+  padding: 4px 8px;
+  margin-bottom: 4px;
+  border-bottom: 1px solid var(--border-color, #3a3a3a);
 }
 
 .selectActions {
   display: flex;
-  gap: var(--spacing-xs, 4px);
+  gap: 4px;
+  margin-bottom: 8px;
 }
 
 .actionButton {
-  padding: 2px 8px;
-  border: 1px solid var(--color-border);
-  border-radius: var(--border-radius-sm, 4px);
-  background: var(--color-bg-secondary);
-  color: var(--color-text-secondary);
-  font-size: var(--font-size-xs, 0.75rem);
+  flex: 1;
+  padding: 4px 8px;
+  border: 1px solid var(--border-color, #3a3a3a);
+  border-radius: 4px;
+  background: var(--bg-secondary, #252525);
+  color: var(--text-secondary, #888);
+  font-size: 0.75rem;
   cursor: pointer;
   transition: all 0.2s ease;
 }
 
 .actionButton:hover:not(:disabled) {
-  background: var(--color-bg-hover);
-  border-color: var(--color-primary);
+  background: var(--bg-hover, #3a3a3a);
+  color: var(--text-primary, #fff);
+}
+
+.actionButton.active {
+  background: var(--primary-color, #f25843);
+  border-color: var(--primary-color, #f25843);
+  color: #fff;
 }
 
 .actionButton:disabled {
@@ -179,24 +136,27 @@
 .checkboxList {
   display: flex;
   flex-direction: column;
-  gap: var(--spacing-xs, 4px);
-  padding: var(--spacing-sm, 8px);
-  background: var(--color-bg-secondary);
-  border-radius: var(--border-radius-md, 6px);
+  gap: 2px;
+  padding: 4px;
+  background: var(--bg-secondary, #252525);
+  border-radius: 4px;
+  max-height: 200px;
+  overflow-y: auto;
 }
 
 .checkboxItem {
   display: flex;
   align-items: center;
-  gap: var(--spacing-sm, 8px);
-  padding: var(--spacing-xs, 4px) var(--spacing-sm, 8px);
-  border-radius: var(--border-radius-sm, 4px);
+  gap: 8px;
+  padding: 6px 8px;
+  border-radius: 4px;
   cursor: pointer;
-  transition: background 0.2s ease;
+  transition: background 0.15s ease;
+  color: var(--text-primary, #e0e0e0);
 }
 
 .checkboxItem:hover {
-  background: var(--color-bg-hover);
+  background: var(--bg-hover, #3a3a3a);
 }
 
 .checkboxItem.disabled {
@@ -205,34 +165,35 @@
 }
 
 .checkboxItem input[type="checkbox"] {
-  width: 16px;
-  height: 16px;
+  width: 14px;
+  height: 14px;
   cursor: inherit;
+  accent-color: var(--primary-color, #f25843);
 }
 
 .icon {
-  font-size: 1.1em;
+  font-size: 1rem;
 }
 
 .providerName {
-  font-size: var(--font-size-sm, 0.875rem);
-  color: var(--color-text-primary);
+  font-size: 0.8rem;
+  color: var(--text-primary, #e0e0e0);
 }
 
 .hint {
-  font-size: var(--font-size-xs, 0.75rem);
-  color: var(--color-text-tertiary);
-  font-style: italic;
-  padding: var(--spacing-xs, 4px) 0;
+  font-size: 0.7rem;
+  color: var(--text-tertiary, #666);
+  text-align: center;
+  padding: 4px 0;
 }
 
 .loading {
   display: flex;
   align-items: center;
   justify-content: center;
-  padding: var(--spacing-md, 16px);
-  color: var(--color-text-secondary);
-  font-size: var(--font-size-sm, 0.875rem);
+  padding: 12px;
+  color: var(--text-secondary, #888);
+  font-size: 0.8rem;
 }
 
 /* ============================================================================
diff --git a/src/components/ProviderSelector/ProviderSelector.tsx b/src/components/ProviderSelector/ProviderSelector.tsx
index 73f0184..55596a8 100644
--- a/src/components/ProviderSelector/ProviderSelector.tsx
+++ b/src/components/ProviderSelector/ProviderSelector.tsx
@@ -10,7 +10,7 @@
  * - Lädt verfügbare Provider aus dem Billing-System
  */
 
-import React, { useEffect, useMemo, useState } from 'react';
+import React, { useEffect, useMemo, useState, useRef, useCallback } from 'react';
 import { useBilling } from '../../hooks/useBilling';
 import styles from './ProviderSelector.module.css';
 
@@ -20,6 +20,7 @@ const PROVIDER_LABELS: Record<string, string> = {
   openai: 'OpenAI (GPT)',
   perplexity: 'Perplexity',
   tavily: 'Tavily (Web Search)',
+  privatellm: 'Private LLM',
   internal: 'Internal',
 };
 
@@ -29,6 +30,7 @@ const PROVIDER_ICONS: Record<string, string> = {
   openai: '💬',
   perplexity: '🔍',
   tavily: '🌐',
+  privatellm: '🔒',
   internal: '🏠',
 };
 
@@ -112,6 +114,7 @@ export const ProviderMultiSelect: React.FC<ProviderMultiSelectProps> = ({
   defaultExpanded = false,
 }) => {
   const [isExpanded, setIsExpanded] = useState(defaultExpanded);
+  const containerRef = useRef<HTMLDivElement>(null);
   const { allowedProviders, loadAllowedProviders, loading } = useBilling();
   
   useEffect(() => {
@@ -120,66 +123,84 @@ export const ProviderMultiSelect: React.FC<ProviderMultiSelectProps> = ({
     }
   }, []);
   
+  // Click outside handler
+  const handleClickOutside = useCallback((event: MouseEvent) => {
+    if (containerRef.current && !containerRef.current.contains(event.target as Node)) {
+      setIsExpanded(false);
+    }
+  }, []);
+  
+  useEffect(() => {
+    if (isExpanded) {
+      document.addEventListener('mousedown', handleClickOutside);
+      return () => document.removeEventListener('mousedown', handleClickOutside);
+    }
+  }, [isExpanded, handleClickOutside]);
+  
+  // Check if all providers are selected (or none selected = all used)
+  const isAllSelected = selectedProviders.length === 0 || 
+    (allowedProviders.length > 0 && selectedProviders.length === allowedProviders.length);
+  
+  // For checkbox display: if none selected, show all as checked (since all are used)
+  const effectiveSelection = selectedProviders.length === 0 ? allowedProviders : selectedProviders;
+  
   const handleToggle = (provider: string) => {
-    if (selectedProviders.includes(provider)) {
-      onChange(selectedProviders.filter((p) => p !== provider));
+    // Use effectiveSelection for toggle logic (handles empty = all case)
+    if (effectiveSelection.includes(provider)) {
+      // Deactivate: remove from effective selection
+      onChange(effectiveSelection.filter((p) => p !== provider));
     } else {
-      onChange([...selectedProviders, provider]);
+      // Activate: add to effective selection
+      onChange([...effectiveSelection, provider]);
     }
   };
   
   const handleSelectAll = () => {
-    onChange(allowedProviders);
+    onChange([...allowedProviders]);
   };
   
   const handleSelectNone = () => {
     onChange([]);
   };
   
-  // Summary text for collapsed view
-  const summaryText = useMemo(() => {
-    if (selectedProviders.length === 0) {
-      return 'Alle Provider';
-    }
-    if (selectedProviders.length === 1) {
-      return PROVIDER_LABELS[selectedProviders[0]] || selectedProviders[0];
-    }
-    return `${selectedProviders.length} Provider`;
-  }, [selectedProviders]);
-  
-  // Summary icons for collapsed view
-  const summaryIcons = useMemo(() => {
-    if (selectedProviders.length === 0) {
+  // Summary icon for button
+  const summaryIcon = useMemo(() => {
+    if (selectedProviders.length === 0 || selectedProviders.length === allowedProviders.length) {
       return '🤖';
     }
-    return selectedProviders.slice(0, 3).map(p => PROVIDER_ICONS[p] || '🔌').join('');
-  }, [selectedProviders]);
+    if (selectedProviders.length === 1) {
+      return PROVIDER_ICONS[selectedProviders[0]] || '🔌';
+    }
+    return '🤖';
+  }, [selectedProviders, allowedProviders]);
   
   return (
-    <div className={`${styles.providerMultiSelect} ${className || ''} ${isExpanded ? styles.expanded : styles.collapsed}`}>
-      {/* Collapsible Header */}
+    <div 
+      ref={containerRef}
+      className={`${styles.providerMultiSelect} ${className || ''} ${isExpanded ? styles.expanded : styles.collapsed}`}
+    >
+      {/* Trigger Button - styled like iconButton */}
       <button 
         type="button"
-        className={styles.collapseHeader}
+        className={styles.triggerButton}
         onClick={() => setIsExpanded(!isExpanded)}
         disabled={disabled}
+        title="Provider auswählen"
       >
-        <span className={styles.summaryIcons}>{summaryIcons}</span>
-        <span className={styles.summaryText}>{summaryText}</span>
-        <span className={styles.expandIcon}>{isExpanded ? '▲' : '▼'}</span>
+        <span className={styles.buttonIcon}>{summaryIcon}</span>
       </button>
       
-      {/* Expandable Content */}
+      {/* Dropdown Content */}
       {isExpanded && (
-        <div className={styles.expandableContent}>
-          {showLabel && <label className={styles.label}>{label}</label>}
+        <div className={styles.dropdownContent}>
+          {showLabel && <div className={styles.dropdownHeader}>{label}</div>}
           
           <div className={styles.selectActions}>
             <button 
               type="button" 
               onClick={handleSelectAll} 
               disabled={disabled}
-              className={styles.actionButton}
+              className={`${styles.actionButton} ${isAllSelected ? styles.active : ''}`}
             >
               Alle
             </button>
@@ -194,7 +215,7 @@ export const ProviderMultiSelect: React.FC<ProviderMultiSelectProps> = ({
           </div>
           
           {loading ? (
-            <div className={styles.loading}>Lade Provider...</div>
+            <div className={styles.loading}>Lade...</div>
           ) : (
             <div className={styles.checkboxList}>
               {allowedProviders.map((provider) => (
@@ -204,7 +225,7 @@ export const ProviderMultiSelect: React.FC<ProviderMultiSelectProps> = ({
                 >
                   <input
                     type="checkbox"
-                    checked={selectedProviders.includes(provider)}
+                    checked={effectiveSelection.includes(provider)}
                     onChange={() => handleToggle(provider)}
                     disabled={disabled}
                   />
@@ -219,7 +240,7 @@ export const ProviderMultiSelect: React.FC<ProviderMultiSelectProps> = ({
           
           {selectedProviders.length === 0 && !loading && (
             <div className={styles.hint}>
-              Wenn keine Provider ausgewählt sind, werden alle erlaubten Provider verwendet.
+              Alle Provider aktiv
             </div>
           )}
         </div>
diff --git a/src/components/UiComponents/Messages/ChatMessages/ChatMessage.tsx b/src/components/UiComponents/Messages/ChatMessages/ChatMessage.tsx
index 169bd72..aff1272 100644
--- a/src/components/UiComponents/Messages/ChatMessages/ChatMessage.tsx
+++ b/src/components/UiComponents/Messages/ChatMessages/ChatMessage.tsx
@@ -1,6 +1,7 @@
 import React from 'react';
 import ReactMarkdown from 'react-markdown';
 import remarkGfm from 'remark-gfm';
+import { FaExclamationTriangle } from 'react-icons/fa';
 import { Message } from '../MessagesTypes';
 import { formatTimestamp } from '../MessageUtils';
 import { DocumentItem, ActionInfo } from '../MessageParts';
@@ -40,7 +41,9 @@ export const ChatMessage: React.FC<ChatMessageProps> = ({
   workflowId
 }) => {
   const isUser = message.role?.toLowerCase() === 'user';
+  const isError = message.actionProgress === 'fail' || message.actionProgress === 'error';
   const messageClass = isUser ? styles.messageUser : styles.messageAssistant;
+  const errorClass = isError ? styles.messageError : '';
 
   // Debug: Log documents if in dev mode
   if (import.meta.env.DEV && message.documents) {
@@ -48,8 +51,16 @@ export const ChatMessage: React.FC<ChatMessageProps> = ({
   }
 
   return (
-    <div className={`${styles.message} ${messageClass}`}>
+    <div className={`${styles.message} ${messageClass} ${errorClass}`}>
       <div className={styles.messageBubble}>
+        {/* Error indicator for failed actions */}
+        {isError && (
+          <div className={styles.errorIndicator}>
+            <FaExclamationTriangle className={styles.errorIcon} />
+            <span>Aktion fehlgeschlagen</span>
+          </div>
+        )}
+        
         {/* Message content */}
         {message.message && (
           <div className={styles.messageContent}>
diff --git a/src/components/UiComponents/Messages/Messages.module.css b/src/components/UiComponents/Messages/Messages.module.css
index e5741d5..620e4ac 100644
--- a/src/components/UiComponents/Messages/Messages.module.css
+++ b/src/components/UiComponents/Messages/Messages.module.css
@@ -64,6 +64,29 @@
   border-bottom-left-radius: 4px;
 }
 
+/* Error/Failed Messages */
+.messageError .messageBubble {
+  background-color: var(--danger-bg, #fee2e2);
+  border: 1px solid var(--danger-color, #dc2626);
+}
+
+.errorIndicator {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  color: var(--danger-color, #dc2626);
+  font-size: 12px;
+  font-weight: 500;
+  padding: 4px 8px;
+  background-color: rgba(220, 38, 38, 0.1);
+  border-radius: 4px;
+  margin-bottom: 4px;
+}
+
+.errorIcon {
+  font-size: 14px;
+}
+
 /* Message Metadata */
 .messageMetadata {
   display: flex;
diff --git a/src/hooks/playground/useWorkflowLifecycle.ts b/src/hooks/playground/useWorkflowLifecycle.ts
index 039864f..e553a68 100644
--- a/src/hooks/playground/useWorkflowLifecycle.ts
+++ b/src/hooks/playground/useWorkflowLifecycle.ts
@@ -18,7 +18,54 @@ interface UnifiedChatDataItem {
   createdAt: number;
 }
 
+/**
+ * =============================================================================
+ * WORKFLOW LIFECYCLE STATE MACHINE
+ * =============================================================================
+ * 
+ * WORKFLOW STATUS (from Backend):
+ *   • idle      - No workflow
+ *   • running   - Workflow is processing
+ *   • completed - Round finished (Backend processed "last" message)
+ *   • stopped   - User stopped the workflow
+ *   • failed    - Error occurred
+ * 
+ * UI FLAG:
+ *   • hasRenderedLastMessage: boolean
+ *     - true:  "last" message was rendered in UI
+ *     - false: "last" message not yet in UI
+ * 
+ * POLLING LOGIC:
+ *   POLL ACTIVE when:
+ *     status === 'running'
+ *     OR (status === 'completed' AND !hasRenderedLastMessage)
+ * 
+ *   POLL STOPS when:
+ *     status === 'stopped'
+ *     OR status === 'failed'
+ *     OR hasRenderedLastMessage === true
+ * 
+ * TRANSITIONS:
+ *   [Send Button] (from any status):
+ *     → hasRenderedLastMessage = false (new round starts)
+ *     → afterTimestamp = now
+ *     → Start polling
+ * 
+ *   [Load Workflow]:
+ *     → Load all data
+ *     → Check if last message has status="last"
+ *     → If yes: hasRenderedLastMessage = true, no polling
+ *     → If no AND status=running: Start polling
+ * 
+ *   [Message with status="last" rendered]:
+ *     → hasRenderedLastMessage = true
+ *     → Stop polling
+ * 
+ * =============================================================================
+ */
+
 export function useWorkflowLifecycle(instanceId: string) {
+  // === STATE ===
   const [workflowId, setWorkflowId] = useState<string | null>(null);
   const [workflowStatus, setWorkflowStatus] = useState<string>('idle');
   const [currentRound, setCurrentRound] = useState<number | undefined>(undefined);
@@ -26,48 +73,35 @@ export function useWorkflowLifecycle(instanceId: string) {
   const [logs, setLogs] = useState<WorkflowLog[]>([]);
   const [dashboardLogs, setDashboardLogs] = useState<WorkflowLog[]>([]);
   const [unifiedContentLogs, setUnifiedContentLogs] = useState<WorkflowLog[]>([]);
-  const [statusChangedFromRunningAt, setStatusChangedFromRunningAt] = useState<number | null>(null);
   const [latestStats, setLatestStats] = useState<{ priceUsd?: number; processingTime?: number; bytesSent?: number; bytesReceived?: number } | null>(null);
-  const prevStatusRef = useRef<string>('idle');
+  
+  // === REFS FOR SYNC ACCESS ===
   const statusRef = useRef<string>('idle');
-  const statusChangedFromRunningAtRef = useRef<number | null>(null);
   const lastRenderedTimestampRef = useRef<number | null>(null);
-  // Track processed stat IDs to avoid double-counting
   const processedStatIdsRef = useRef<Set<string>>(new Set());
-  // Track cumulative stats
   const cumulativeStatsRef = useRef({ priceUsd: 0, processingTime: 0, bytesSent: 0, bytesReceived: 0 });
+  
+  // === KEY STATE MACHINE FLAG ===
+  // This flag tracks if the UI has rendered a message with status="last"
+  // Polling continues until this is true (even if backend status is "completed")
+  const hasRenderedLastMessageRef = useRef<boolean>(false);
+  const [hasRenderedLastMessage, setHasRenderedLastMessage] = useState<boolean>(false);
+  
+  // === HOOKS ===
   const { startWorkflow, stopWorkflow, startingWorkflow, stoppingWorkflows } = useWorkflowOperations();
   const { request } = useApiRequest();
   const pollingController = useWorkflowPolling();
-  
-  // Store polling controller methods in refs to avoid dependency issues
   const pollingControllerRef = useRef(pollingController);
   pollingControllerRef.current = pollingController;
-  
-  // Helper to update status and track transitions
+
+  // === HELPER: Update workflow status ===
   const updateWorkflowStatus = useCallback((newStatus: string) => {
-    const prevStatus = prevStatusRef.current;
-    prevStatusRef.current = newStatus;
     statusRef.current = newStatus;
     setWorkflowStatus(newStatus);
-    
-    // Track when status changes from 'running' to something else
-    if (prevStatus === 'running' && newStatus !== 'running') {
-      const timestamp = Date.now();
-      setStatusChangedFromRunningAt(timestamp);
-      statusChangedFromRunningAtRef.current = timestamp;
-    } else if (newStatus === 'running') {
-      setStatusChangedFromRunningAt(null);
-      statusChangedFromRunningAtRef.current = null;
-    }
+    console.log('📍 Status updated to:', newStatus);
   }, []);
-  
-  // Expose setWorkflowStatus for optimistic updates
-  const setWorkflowStatusOptimistic = useCallback((status: string) => {
-    updateWorkflowStatus(status);
-  }, [updateWorkflowStatus]);
 
-  // Convert backend log format to frontend format
+  // === HELPER: Convert backend log format to frontend format ===
   const convertLogToFrontendFormat = useCallback((log: any): WorkflowLog => {
     return {
       id: log.id,
@@ -83,15 +117,15 @@ export function useWorkflowLifecycle(instanceId: string) {
     };
   }, [workflowId]);
 
-  // Process unified chat data chronologically
+  // === CORE: Process unified chat data ===
   const processUnifiedChatData = useCallback((chatData: { messages: WorkflowMessage[]; logs: WorkflowLog[]; stats: any[] }) => {
-    console.log('🔄 Processing unified chat data:', {
+    console.log('🔄 Processing chat data:', {
       messages: chatData.messages?.length || 0,
       logs: chatData.logs?.length || 0,
       stats: chatData.stats?.length || 0
     });
     
-    // Build unified timeline of all items
+    // Build unified timeline
     const timeline: UnifiedChatDataItem[] = [];
 
     // Add messages
@@ -112,154 +146,132 @@ export function useWorkflowLifecycle(instanceId: string) {
       });
     });
 
-    // Add stats (if needed)
-    (chatData.stats || []).forEach((stat: any) => {
+    // Add stats
+    const rawStats = chatData.stats || [];
+    rawStats.forEach((stat: any) => {
       timeline.push({
         type: 'stat',
         item: stat,
-        createdAt: stat.timestamp || stat.createdAt || Date.now()
+        createdAt: stat._createdAt || stat.createdAt || Date.now()
       });
     });
 
-    console.log('📋 Timeline created with', timeline.length, 'items');
-
     // Sort chronologically
     timeline.sort((a, b) => a.createdAt - b.createdAt);
 
-    // Process items sequentially to maintain chronological order
-    // Update lastRenderedTimestamp after processing all items (use latest timestamp)
+    // Update lastRenderedTimestamp
     if (timeline.length > 0) {
-      const latestTimestamp = timeline[timeline.length - 1].createdAt;
-      lastRenderedTimestampRef.current = latestTimestamp;
+      lastRenderedTimestampRef.current = timeline[timeline.length - 1].createdAt;
     }
 
-    // Use functional updates to avoid dependency on current state
+    // === CHECK FOR "LAST" MESSAGE ===
+    // This is the key state machine logic: detect when a "last" message arrives
+    let foundLastMessage = false;
+    
+    timeline.forEach((item) => {
+      if (item.type === 'message') {
+        const message = item.item as WorkflowMessage;
+        if ((message as any).status === 'last') {
+          foundLastMessage = true;
+          console.log('🏁 Found "last" message:', message.id);
+        }
+      }
+    });
+
+    // === STATE MACHINE: Handle "last" message ===
+    if (foundLastMessage && !hasRenderedLastMessageRef.current) {
+      console.log('🛑 "last" message detected - stopping polling');
+      hasRenderedLastMessageRef.current = true;
+      setHasRenderedLastMessage(true);
+      pollingControllerRef.current.stopPolling();
+    }
+
+    // === UPDATE MESSAGES STATE ===
     setMessages(prevMessages => {
       const newMessages: WorkflowMessage[] = [...prevMessages];
       let hasChanges = false;
-      let messagesAdded = 0;
-      let messagesUpdated = 0;
       
       timeline.forEach((item) => {
         if (item.type === 'message') {
           const message = item.item as WorkflowMessage;
+          if (!message || !message.id) return;
           
-          if (!message || !message.id) {
-            console.warn('⚠️ Invalid message in timeline:', message);
-            return;
-          }
-          
-          // Check if message already exists
           const existingIndex = newMessages.findIndex(m => m.id === message.id);
           if (existingIndex >= 0) {
-            // Always update existing message (don't compare, just update)
             newMessages[existingIndex] = message;
             hasChanges = true;
-            messagesUpdated++;
           } else {
             newMessages.push(message);
             hasChanges = true;
-            messagesAdded++;
           }
         }
       });
 
-      console.log(`📨 Messages: ${messagesAdded} added, ${messagesUpdated} updated, total: ${newMessages.length}`);
-      if (messagesAdded > 0 || messagesUpdated > 0) {
-        console.log('📨 Sample messages:', newMessages.slice(0, 3).map(m => ({ id: m.id, message: m.message?.substring(0, 50) })));
-      }
-
-      // Always return sorted array if we processed any messages
       if (hasChanges || timeline.some(item => item.type === 'message')) {
-        const sorted = [...newMessages].sort(sortMessages);
-        console.log(`✅ Returning ${sorted.length} sorted messages`);
-        return sorted;
+        return [...newMessages].sort(sortMessages);
       }
-
-      console.log('⚠️ No changes detected, returning previous messages');
       return prevMessages;
     });
 
-    setDashboardLogs(prevDashboardLogs => {
-      const newDashboardLogs: WorkflowLog[] = [...prevDashboardLogs];
+    // === UPDATE DASHBOARD LOGS (with operationId) ===
+    setDashboardLogs(prevLogs => {
+      const newLogs: WorkflowLog[] = [...prevLogs];
       let hasChanges = false;
       
       timeline.forEach((item) => {
         if (item.type === 'log') {
-          const backendLog = item.item as any;
-          const frontendLog = convertLogToFrontendFormat(backendLog);
-
-          // Route logs based on operationId
+          const frontendLog = convertLogToFrontendFormat(item.item);
           if (frontendLog.operationId) {
-            // Logs WITH operationId → Dashboard
-            const existingIndex = newDashboardLogs.findIndex(l => l.id === frontendLog.id);
+            const existingIndex = newLogs.findIndex(l => l.id === frontendLog.id);
             if (existingIndex >= 0) {
-              // Check if log actually changed
-              const existingLog = newDashboardLogs[existingIndex];
-              if (JSON.stringify(existingLog) !== JSON.stringify(frontendLog)) {
-                newDashboardLogs[existingIndex] = frontendLog;
+              if (JSON.stringify(newLogs[existingIndex]) !== JSON.stringify(frontendLog)) {
+                newLogs[existingIndex] = frontendLog;
                 hasChanges = true;
               }
             } else {
-              newDashboardLogs.push(frontendLog);
+              newLogs.push(frontendLog);
               hasChanges = true;
             }
           }
         }
       });
 
-      // Only return new array if there are changes
-      if (!hasChanges) {
-        return prevDashboardLogs;
-      }
-
-      return [...newDashboardLogs].sort(sortLogs);
+      return hasChanges ? [...newLogs].sort(sortLogs) : prevLogs;
     });
 
-    setUnifiedContentLogs(prevUnifiedContentLogs => {
-      const newUnifiedContentLogs: WorkflowLog[] = [...prevUnifiedContentLogs];
+    // === UPDATE UNIFIED CONTENT LOGS (without operationId) ===
+    setUnifiedContentLogs(prevLogs => {
+      const newLogs: WorkflowLog[] = [...prevLogs];
       let hasChanges = false;
       
       timeline.forEach((item) => {
         if (item.type === 'log') {
-          const backendLog = item.item as any;
-          const frontendLog = convertLogToFrontendFormat(backendLog);
-
-          // Route logs based on operationId
+          const frontendLog = convertLogToFrontendFormat(item.item);
           if (!frontendLog.operationId) {
-            // Logs WITHOUT operationId → Unified Content Area
-            const existingIndex = newUnifiedContentLogs.findIndex(l => l.id === frontendLog.id);
+            const existingIndex = newLogs.findIndex(l => l.id === frontendLog.id);
             if (existingIndex >= 0) {
-              // Check if log actually changed
-              const existingLog = newUnifiedContentLogs[existingIndex];
-              if (JSON.stringify(existingLog) !== JSON.stringify(frontendLog)) {
-                newUnifiedContentLogs[existingIndex] = frontendLog;
+              if (JSON.stringify(newLogs[existingIndex]) !== JSON.stringify(frontendLog)) {
+                newLogs[existingIndex] = frontendLog;
                 hasChanges = true;
               }
             } else {
-              newUnifiedContentLogs.push(frontendLog);
+              newLogs.push(frontendLog);
               hasChanges = true;
             }
           }
         }
       });
 
-      // Only return new array if there are changes
-      if (!hasChanges) {
-        return prevUnifiedContentLogs;
-      }
-
-      return [...newUnifiedContentLogs].sort(sortLogs);
+      return hasChanges ? [...newLogs].sort(sortLogs) : prevLogs;
     });
 
-    // Update combined logs for backward compatibility (using functional update)
+    // === UPDATE COMBINED LOGS ===
     setLogs(prevLogs => {
       const allLogs: WorkflowLog[] = [...prevLogs];
       
       timeline.forEach((item) => {
         if (item.type === 'log') {
-          const backendLog = item.item as any;
-          const frontendLog = convertLogToFrontendFormat(backendLog);
+          const frontendLog = convertLogToFrontendFormat(item.item);
           const existingIndex = allLogs.findIndex(l => l.id === frontendLog.id);
           if (existingIndex >= 0) {
             allLogs[existingIndex] = frontendLog;
@@ -272,47 +284,36 @@ export function useWorkflowLifecycle(instanceId: string) {
       return [...allLogs].sort(sortLogs);
     });
 
-    // Process stats - aggregate only NEW stat entries (avoid double-counting)
+    // === PROCESS STATS ===
     const statsItems = timeline.filter(item => item.type === 'stat');
+    
     if (statsItems.length > 0) {
       let hasNewStats = false;
       
       statsItems.forEach(statItem => {
-        const statData = statItem.item || statItem;
-        const statId = statData?.id || (statItem as any).id;
+        const statData = statItem.item;
+        const statId = statData?.id;
         
-        // Skip if already processed
         if (statId && processedStatIdsRef.current.has(statId)) {
-          return;
+          return; // Skip already processed
         }
         
         if (statData) {
           hasNewStats = true;
-          
-          // Mark as processed
           if (statId) {
             processedStatIdsRef.current.add(statId);
           }
           
-          // Add to cumulative stats
-          if (statData.priceUsd !== undefined && statData.priceUsd !== null) {
-            cumulativeStatsRef.current.priceUsd += statData.priceUsd;
-          }
-          if (statData.processingTime !== undefined && statData.processingTime !== null) {
-            cumulativeStatsRef.current.processingTime += statData.processingTime;
-          }
-          if (statData.bytesSent !== undefined && statData.bytesSent !== null) {
-            cumulativeStatsRef.current.bytesSent += statData.bytesSent;
-          }
-          if (statData.bytesReceived !== undefined && statData.bytesReceived !== null) {
-            cumulativeStatsRef.current.bytesReceived += statData.bytesReceived;
-          }
+          // Accumulate stats
+          const price = statData.priceCHF ?? statData.priceUsd ?? 0;
+          if (price > 0) cumulativeStatsRef.current.priceUsd += price;
+          if (statData.processingTime) cumulativeStatsRef.current.processingTime += statData.processingTime;
+          if (statData.bytesSent) cumulativeStatsRef.current.bytesSent += statData.bytesSent;
+          if (statData.bytesReceived) cumulativeStatsRef.current.bytesReceived += statData.bytesReceived;
         }
       });
       
-      // Update state with cumulative totals
-      if (hasNewStats || (cumulativeStatsRef.current.bytesSent > 0 || cumulativeStatsRef.current.bytesReceived > 0 || 
-          cumulativeStatsRef.current.processingTime > 0 || cumulativeStatsRef.current.priceUsd > 0)) {
+      if (hasNewStats) {
         setLatestStats({
           priceUsd: cumulativeStatsRef.current.priceUsd,
           processingTime: cumulativeStatsRef.current.processingTime,
@@ -323,10 +324,9 @@ export function useWorkflowLifecycle(instanceId: string) {
     }
   }, [convertLogToFrontendFormat]);
 
-  // Poll workflow data using unified chat data endpoint
+  // === POLLING FUNCTION ===
   const pollWorkflowData = useCallback(async (id: string) => {
     try {
-      // Determine afterTimestamp for incremental polling
       const afterTimestamp = lastRenderedTimestampRef.current || undefined;
 
       // Fetch workflow status
@@ -334,192 +334,73 @@ export function useWorkflowLifecycle(instanceId: string) {
       
       if (workflowData) {
         const status = workflowData.status || 'idle';
-        const round = workflowData.currentRound !== undefined ? workflowData.currentRound : undefined;
+        const round = workflowData.currentRound;
         
         updateWorkflowStatus(status);
-        setCurrentRound(round);
+        if (round !== undefined) setCurrentRound(round);
+        
+        // === STATE MACHINE: Check if polling should stop based on status ===
+        if (status === 'stopped' || status === 'failed') {
+          console.log(`🛑 Workflow ${status} - stopping polling immediately`);
+          pollingControllerRef.current.stopPolling();
+          return;
+        }
       }
 
-      // Fetch unified chat data
+      // Fetch chat data
       const chatData = await fetchChatData(request, instanceId, id, afterTimestamp);
       
-      console.log('📊 Processed chat data:', {
-        messagesCount: chatData.messages?.length || 0,
-        logsCount: chatData.logs?.length || 0,
-        statsCount: chatData.stats?.length || 0,
-        afterTimestamp: afterTimestamp
+      console.log('📊 Polled chat data:', {
+        messages: chatData.messages?.length || 0,
+        logs: chatData.logs?.length || 0,
+        stats: chatData.stats?.length || 0,
+        afterTimestamp
       });
       
-      // If we got empty results and we're using afterTimestamp, the backend might be filtering incorrectly
-      // Reset timestamp to null so next poll fetches all items (but only if we have existing data)
-      const hasNoNewData = (chatData.messages?.length || 0) === 0 && 
-                           (chatData.logs?.length || 0) === 0 && 
-                           (chatData.stats?.length || 0) === 0;
-      
-      // Only reset if we're using afterTimestamp and got empty results
-      // This handles cases where backend filtering might miss items due to timestamp precision issues
-      if (hasNoNewData && afterTimestamp !== undefined && lastRenderedTimestampRef.current !== null) {
-        console.warn('⚠️ Got empty results with afterTimestamp, resetting timestamp for next poll');
-        // Don't reset immediately - let this poll complete, next poll will fetch all
-        lastRenderedTimestampRef.current = null;
-      }
-      
-      // Process unified chat data
+      // Process data (this will detect "last" message and stop polling if found)
       processUnifiedChatData(chatData);
-
-      // Determine if polling should continue
-      const currentStatus = statusRef.current;
       
-      // Stop polling immediately for failed or stopped workflows
-      // For completed workflows, allow grace period (handled by useEffect)
-      if (currentStatus === 'failed' || currentStatus === 'stopped') {
-        pollingControllerRef.current.stopPolling();
-        return;
-      }
-
-      // Continue polling for 'running' status
-      // For 'completed' status, continue if within grace period (handled by useEffect)
-      // Polling will be stopped by the useEffect when grace period expires or status changes to failed/stopped
-    } catch (error: any) {
-      // Handle rate limiting (429 errors)
-      if (error?.status === 429 || error?.response?.status === 429) {
-        throw error; // Let polling controller handle rate limit backoff
-      }
-      console.error('Error polling workflow data:', error);
-      // Don't throw for other errors - allow polling to continue with backoff
-    }
-  }, [request, updateWorkflowStatus, processUnifiedChatData]);
-
-  // Load initial workflow data (non-polling)
-  const _loadWorkflowData = useCallback(async (id: string) => {
-    try {
-      const workflowData = await fetchWorkflowApi(request, id).catch(() => null);
-      
-      if (!workflowData) {
-        setMessages([]);
-        setLogs([]);
-        setDashboardLogs([]);
-        setUnifiedContentLogs([]);
-        setLatestStats(null);
-        // Reset stats tracking
-        processedStatIdsRef.current.clear();
-        cumulativeStatsRef.current = { priceUsd: 0, processingTime: 0, bytesSent: 0, bytesReceived: 0 };
-        return;
-      }
-      
-      const messagesData = Array.isArray(workflowData.messages) ? workflowData.messages : [];
-      const logsData = Array.isArray(workflowData.logs) ? workflowData.logs : [];
-      const status = workflowData.status || 'idle';
-      const round = workflowData.currentRound !== undefined ? workflowData.currentRound : undefined;
-      
-      updateWorkflowStatus(status);
-      setCurrentRound(round);
-      
-      // Always fetch unified chat data to get all messages and logs
-      // Reset lastRenderedTimestamp to fetch all historical data
-      lastRenderedTimestampRef.current = null;
-      try {
-        const chatData = await fetchChatData(request, instanceId, id, undefined);
-        console.log('📥 loadWorkflowData: Fetched unified chat data:', {
-          messagesCount: chatData.messages?.length || 0,
-          logsCount: chatData.logs?.length || 0
-        });
-        processUnifiedChatData(chatData);
-      } catch (error) {
-        console.warn('⚠️ Failed to fetch unified chat data, falling back to workflowData:', error);
-        // Fallback to workflowData if unified chat data fails
-        if (messagesData.length > 0) {
-          setMessages([...messagesData].sort(sortMessages));
-        }
-        
-        // Process logs and separate by operationId
-        const dashboardLogsList: WorkflowLog[] = [];
-        const unifiedContentLogsList: WorkflowLog[] = [];
-        
-        logsData.forEach((log: any) => {
-          const frontendLog = convertLogToFrontendFormat(log);
-          if (frontendLog.operationId) {
-            dashboardLogsList.push(frontendLog);
-          } else {
-            unifiedContentLogsList.push(frontendLog);
-          }
-        });
-
-        setDashboardLogs(dashboardLogsList.sort(sortLogs));
-        setUnifiedContentLogs(unifiedContentLogsList.sort(sortLogs));
-        setLogs([...dashboardLogsList, ...unifiedContentLogsList].sort(sortLogs));
-      }
     } catch (error) {
-      console.error('Error loading workflow data:', error);
+      console.error('❌ Polling error:', error);
     }
-  }, [request, updateWorkflowStatus, convertLogToFrontendFormat, processUnifiedChatData]);
-  void _loadWorkflowData; // Intentionally unused, reserved for future use
+  }, [request, instanceId, updateWorkflowStatus, processUnifiedChatData]);
 
-  // Set up polling when workflow is running
+  // === POLLING CONTROL EFFECT ===
   useEffect(() => {
     if (!workflowId) {
-      // Only clear state if not already cleared to avoid unnecessary updates
-      setMessages(prev => prev.length > 0 ? [] : prev);
-      setLogs(prev => prev.length > 0 ? [] : prev);
-      setDashboardLogs(prev => prev.length > 0 ? [] : prev);
-      setUnifiedContentLogs(prev => prev.length > 0 ? [] : prev);
-      setLatestStats(null);
-      // Reset stats tracking
-      processedStatIdsRef.current.clear();
-      cumulativeStatsRef.current = { priceUsd: 0, processingTime: 0, bytesSent: 0, bytesReceived: 0 };
-      setCurrentRound(prev => prev !== undefined ? undefined : prev);
-      if (statusChangedFromRunningAt !== null) {
-        setStatusChangedFromRunningAt(null);
-        statusChangedFromRunningAtRef.current = null;
-      }
-      lastRenderedTimestampRef.current = null;
       pollingControllerRef.current.stopPolling();
       return;
     }
 
-    // Continue polling if:
-    // 1. Workflow is currently running, OR
-    // 2. Workflow just completed (within last 5 seconds) - grace period to catch final messages
-    // Stop polling for failed or stopped workflows immediately
-    const changedAtRef = statusChangedFromRunningAtRef.current;
-    const gracePeriodMs = 5000; // 5 seconds grace period
-    const timeSinceCompletion = changedAtRef !== null ? Date.now() - changedAtRef : Infinity;
-    const isInGracePeriod = workflowStatus === 'completed' && changedAtRef !== null && timeSinceCompletion < gracePeriodMs;
-    const shouldPoll = workflowStatus === 'running' || isInGracePeriod;
+    // === STATE MACHINE: Determine if polling should be active ===
+    const shouldPoll = 
+      workflowStatus === 'running' || 
+      (workflowStatus === 'completed' && !hasRenderedLastMessage);
+    
+    const shouldStopImmediately = 
+      workflowStatus === 'stopped' || 
+      workflowStatus === 'failed' ||
+      hasRenderedLastMessage;
+
+    console.log('📍 Polling decision:', { 
+      workflowStatus, 
+      hasRenderedLastMessage,
+      shouldPoll,
+      shouldStopImmediately
+    });
 
     if (shouldPoll) {
-      // Start polling
       pollingControllerRef.current.startPolling(workflowId, pollWorkflowData);
-      
-      // If in grace period, set a timer to stop polling after grace period expires
-      if (isInGracePeriod) {
-        const remainingGraceTime = gracePeriodMs - timeSinceCompletion;
-        const graceTimer = setTimeout(() => {
-          pollingControllerRef.current.stopPolling();
-          setStatusChangedFromRunningAt(null);
-          statusChangedFromRunningAtRef.current = null;
-        }, remainingGraceTime + 100); // Small buffer
-        
-        return () => {
-          clearTimeout(graceTimer);
-          pollingControllerRef.current.stopPolling();
-        };
-      }
-    } else {
-      // Stop polling for failed, stopped, or completed (after grace period) workflows
+    } else if (shouldStopImmediately) {
       pollingControllerRef.current.stopPolling();
-      // Clear the status change timestamp when we stop polling
-      if (statusChangedFromRunningAt !== null) {
-        setStatusChangedFromRunningAt(null);
-        statusChangedFromRunningAtRef.current = null;
-      }
     }
 
     return () => {
       pollingControllerRef.current.stopPolling();
     };
-  }, [workflowStatus, workflowId, pollWorkflowData, statusChangedFromRunningAt]);
-  
+  }, [workflowStatus, workflowId, hasRenderedLastMessage, pollWorkflowData]);
+
+  // === START WORKFLOW (Send Button) ===
   const handleStartWorkflow = useCallback(async (
     workflowData: StartWorkflowRequest,
     options?: { workflowId?: string; workflowMode?: 'Dynamic' | 'Automation' }
@@ -529,10 +410,24 @@ export function useWorkflowLifecycle(instanceId: string) {
       
       if (result.success && result.data) {
         const workflow = result.data as Workflow;
+        
+        // === STATE MACHINE: New round starts ===
+        console.log('🚀 Starting workflow:', workflow.id);
+        
+        // Reset state for new round
         setWorkflowId(workflow.id);
+        hasRenderedLastMessageRef.current = false;
+        setHasRenderedLastMessage(false);
+        
+        // Set afterTimestamp to NOW - only poll for new data
+        lastRenderedTimestampRef.current = Date.now();
+        
+        // Start polling immediately
+        pollingControllerRef.current.startPolling(workflow.id, pollWorkflowData);
+        
+        // Update status
         updateWorkflowStatus(workflow.status || 'running');
-        // Reset lastRenderedTimestamp for new workflow
-        lastRenderedTimestampRef.current = null;
+        
         return { success: true, data: result.data };
       } else {
         return { success: false, error: result.error || 'Failed to start workflow' };
@@ -540,8 +435,9 @@ export function useWorkflowLifecycle(instanceId: string) {
     } catch (error: any) {
       return { success: false, error: error.message || 'Failed to start workflow' };
     }
-  }, [instanceId, startWorkflow, updateWorkflowStatus]);
-  
+  }, [instanceId, startWorkflow, updateWorkflowStatus, pollWorkflowData]);
+
+  // === STOP WORKFLOW ===
   const handleStopWorkflow = useCallback(async () => {
     if (!workflowId) {
       return { success: false, error: 'No workflow to stop' };
@@ -552,6 +448,7 @@ export function useWorkflowLifecycle(instanceId: string) {
       
       if (result.success) {
         updateWorkflowStatus('stopped');
+        pollingControllerRef.current.stopPolling();
         return { success: true };
       } else {
         return { success: false, error: result.error || 'Failed to stop workflow' };
@@ -560,31 +457,44 @@ export function useWorkflowLifecycle(instanceId: string) {
       return { success: false, error: error.message || 'Failed to stop workflow' };
     }
   }, [instanceId, workflowId, stopWorkflow, updateWorkflowStatus]);
-  
+
+  // === RESET WORKFLOW ===
   const resetWorkflow = useCallback(() => {
+    console.log('🔄 Resetting workflow state');
+    
     setWorkflowId(null);
-    prevStatusRef.current = 'idle';
-    statusRef.current = 'idle';
     updateWorkflowStatus('idle');
     setCurrentRound(undefined);
+    setMessages([]);
+    setLogs([]);
+    setDashboardLogs([]);
+    setUnifiedContentLogs([]);
     setLatestStats(null);
-    // Reset stats tracking
+    
+    // Reset refs
+    lastRenderedTimestampRef.current = null;
     processedStatIdsRef.current.clear();
     cumulativeStatsRef.current = { priceUsd: 0, processingTime: 0, bytesSent: 0, bytesReceived: 0 };
-    setStatusChangedFromRunningAt(null);
-    statusChangedFromRunningAtRef.current = null;
-    lastRenderedTimestampRef.current = null;
+    hasRenderedLastMessageRef.current = false;
+    setHasRenderedLastMessage(false);
+    
     pollingControllerRef.current.stopPolling();
   }, [updateWorkflowStatus]);
-  
+
+  // === SELECT/LOAD WORKFLOW ===
   const selectWorkflow = useCallback(async (workflowIdToSelect: string) => {
     try {
+      console.log('📥 Loading workflow:', workflowIdToSelect);
+      
+      // Reset state
       setWorkflowId(workflowIdToSelect);
-      // Reset lastRenderedTimestamp and stats for new workflow selection
       lastRenderedTimestampRef.current = null;
       processedStatIdsRef.current.clear();
       cumulativeStatsRef.current = { priceUsd: 0, processingTime: 0, bytesSent: 0, bytesReceived: 0 };
+      hasRenderedLastMessageRef.current = false;
+      setHasRenderedLastMessage(false);
       
+      // Fetch workflow data
       const workflowData = await fetchWorkflowApi(request, workflowIdToSelect).catch(() => null);
       
       if (!workflowData) {
@@ -597,58 +507,66 @@ export function useWorkflowLifecycle(instanceId: string) {
         return;
       }
       
-      const messagesData = Array.isArray(workflowData.messages) ? workflowData.messages : [];
-      const logsData = Array.isArray(workflowData.logs) ? workflowData.logs : [];
       const status = workflowData.status || 'idle';
-      const round = workflowData.currentRound !== undefined ? workflowData.currentRound : undefined;
+      const round = workflowData.currentRound;
       
       updateWorkflowStatus(status);
-      setCurrentRound(round);
+      if (round !== undefined) setCurrentRound(round);
       
-      // Always fetch unified chat data to get all messages and logs (regardless of status)
-      // This ensures completed workflows also show their logs
+      // Fetch all chat data (no afterTimestamp = get everything)
       try {
         const chatData = await fetchChatData(request, instanceId, workflowIdToSelect, undefined);
-        console.log('📥 selectWorkflow: Fetched unified chat data:', {
-          messagesCount: chatData.messages?.length || 0,
-          logsCount: chatData.logs?.length || 0,
-          status
+        console.log('📥 Loaded chat data:', {
+          messages: chatData.messages?.length || 0,
+          logs: chatData.logs?.length || 0,
+          stats: chatData.stats?.length || 0
         });
-        processUnifiedChatData(chatData);
-      } catch (error) {
-        console.warn('⚠️ Failed to fetch unified chat data, falling back to workflowData:', error);
-        // Fallback to workflowData if unified chat data fails
-        if (messagesData.length > 0) {
-          setMessages([...messagesData].sort(sortMessages));
+        
+        // === STATE MACHINE: Check if last message has status="last" ===
+        const allMessages = chatData.messages || [];
+        const sortedMessages = [...allMessages].sort((a, b) => {
+          const aTime = a.publishedAt || a.timestamp || 0;
+          const bTime = b.publishedAt || b.timestamp || 0;
+          return bTime - aTime; // Sort descending (newest first)
+        });
+        
+        const lastMessage = sortedMessages[0];
+        const lastMessageStatus = lastMessage ? (lastMessage as any).status : null;
+        
+        console.log('📍 Last message status:', lastMessageStatus);
+        
+        if (lastMessageStatus === 'last') {
+          // Round is complete - don't start polling
+          hasRenderedLastMessageRef.current = true;
+          setHasRenderedLastMessage(true);
+          console.log('✅ Workflow round complete - no polling needed');
+        } else if (status === 'running') {
+          // Workflow is running - polling will start via useEffect
+          console.log('🔄 Workflow is running - polling will start');
         }
         
-        // Process logs and separate by operationId
-        const dashboardLogsList: WorkflowLog[] = [];
-        const unifiedContentLogsList: WorkflowLog[] = [];
+        // Process the data
+        processUnifiedChatData(chatData);
         
-        logsData.forEach((log: any) => {
-          const frontendLog = convertLogToFrontendFormat(log);
-          if (frontendLog.operationId) {
-            dashboardLogsList.push(frontendLog);
-          } else {
-            unifiedContentLogsList.push(frontendLog);
-          }
-        });
-
-        setDashboardLogs(dashboardLogsList.sort(sortLogs));
-        setUnifiedContentLogs(unifiedContentLogsList.sort(sortLogs));
-        setLogs([...dashboardLogsList, ...unifiedContentLogsList].sort(sortLogs));
+      } catch (error) {
+        console.warn('⚠️ Failed to fetch chat data:', error);
+        updateWorkflowStatus('idle');
       }
       
-      // If workflow is running, polling will start automatically via useEffect
     } catch (error) {
-      console.error('Error selecting workflow:', error);
+      console.error('❌ Error selecting workflow:', error);
     }
-  }, [request, updateWorkflowStatus, convertLogToFrontendFormat, processUnifiedChatData]);
-  
+  }, [request, instanceId, updateWorkflowStatus, processUnifiedChatData]);
+
+  // === EXPOSE STATUS SETTER FOR OPTIMISTIC UPDATES ===
+  const setWorkflowStatusOptimistic = useCallback((status: string) => {
+    updateWorkflowStatus(status);
+  }, [updateWorkflowStatus]);
+
+  // === COMPUTED VALUES ===
   const isRunning = workflowStatus === 'running';
   const isStopping = workflowId ? stoppingWorkflows.has(workflowId) : false;
-  
+
   return {
     workflowId,
     workflowStatus,
@@ -661,6 +579,7 @@ export function useWorkflowLifecycle(instanceId: string) {
     dashboardLogs,
     unifiedContentLogs,
     latestStats,
+    hasRenderedLastMessage,
     startWorkflow: handleStartWorkflow,
     stopWorkflow: handleStopWorkflow,
     resetWorkflow,
diff --git a/src/layouts/FeatureLayout.module.css b/src/layouts/FeatureLayout.module.css
index 5cce883..aeca795 100644
--- a/src/layouts/FeatureLayout.module.css
+++ b/src/layouts/FeatureLayout.module.css
@@ -138,8 +138,12 @@
 /* Feature Content */
 .featureContent {
   flex: 1;
-  overflow: auto;
+  /* Let child components handle their own scrolling for sticky headers */
+  overflow: hidden;
   padding: 1.5rem;
+  /* Maintain flex chain for child components */
+  display: flex;
+  flex-direction: column;
 }
 
 /* Dark Theme */
diff --git a/src/layouts/MainLayout.module.css b/src/layouts/MainLayout.module.css
index f245160..ac71c8b 100644
--- a/src/layouts/MainLayout.module.css
+++ b/src/layouts/MainLayout.module.css
@@ -81,7 +81,8 @@
 /* Content */
 .content {
   flex: 1;
-  overflow: auto;
+  /* Let child components handle their own scrolling for sticky headers */
+  overflow: hidden;
   background: var(--bg-primary, #ffffff);
 }
 
diff --git a/src/pages/admin/Admin.module.css b/src/pages/admin/Admin.module.css
index 50e63ef..6e99486 100644
--- a/src/pages/admin/Admin.module.css
+++ b/src/pages/admin/Admin.module.css
@@ -6,7 +6,12 @@
 
 .adminPage {
   padding: 1.5rem;
-  min-height: 100%;
+  /* Fill parent height and enable flex layout for sticky table headers */
+  height: 100%;
+  max-height: 100%;
+  display: flex;
+  flex-direction: column;
+  overflow: hidden;
 }
 
 .pageHeader {
diff --git a/src/pages/billing/Billing.module.css b/src/pages/billing/Billing.module.css
index 35ce33a..f09b398 100644
--- a/src/pages/billing/Billing.module.css
+++ b/src/pages/billing/Billing.module.css
@@ -6,9 +6,8 @@
 
 .billingDashboard {
   padding: 1.5rem;
-  max-width: 1200px;
-  margin: 0 auto;
   min-height: 100%;
+  width: 100%;
 }
 
 .pageHeader {
@@ -490,7 +489,7 @@
 
 @media (max-width: 768px) {
   .billingDashboard {
-    padding: 1rem;
+    padding: 0.75rem;
   }
   
   .balanceGrid {
diff --git a/src/pages/billing/BillingDashboard.tsx b/src/pages/billing/BillingDashboard.tsx
index 2576818..4e3f963 100644
--- a/src/pages/billing/BillingDashboard.tsx
+++ b/src/pages/billing/BillingDashboard.tsx
@@ -6,6 +6,7 @@
 
 import React, { useState, useEffect, useMemo } from 'react';
 import { useBilling, type BillingBalance, type UsageReport } from '../../hooks/useBilling';
+import { BillingNav } from './BillingNav';
 import styles from './Billing.module.css';
 
 // ============================================================================
@@ -187,6 +188,8 @@ export const BillingDashboard: React.FC = () => {
         <p className={styles.subtitle}>Übersicht über Guthaben und Nutzung</p>
       </header>
       
+      <BillingNav />
+      
       {/* Balance Cards */}
       <section className={styles.section}>
         <h2 className={styles.sectionTitle}>Guthaben</h2>
diff --git a/src/pages/billing/BillingDataView.tsx b/src/pages/billing/BillingDataView.tsx
new file mode 100644
index 0000000..a8ceecc
--- /dev/null
+++ b/src/pages/billing/BillingDataView.tsx
@@ -0,0 +1,443 @@
+/**
+ * BillingDataView
+ * 
+ * Unified billing page with internal tabs:
+ * - Tab "Übersicht": Balance cards + Statistics (from BillingDashboard)
+ * - Tab "Transaktionen": Transaction table with FormGeneratorTable
+ */
+
+import React, { useState, useEffect, useMemo, useCallback } from 'react';
+import { FormGeneratorTable, ColumnConfig } from '../../components/FormGenerator/FormGeneratorTable';
+import api from '../../api';
+import { useBilling, type BillingBalance, type UsageReport } from '../../hooks/useBilling';
+import { UserTransaction } from '../../api/billingApi';
+import styles from './Billing.module.css';
+
+// ============================================================================
+// BALANCE CARD COMPONENT
+// ============================================================================
+
+interface BalanceCardProps {
+  balance: BillingBalance;
+}
+
+const BalanceCard: React.FC<BalanceCardProps> = ({ balance }) => {
+  const formatCurrency = (amount: number) => {
+    return new Intl.NumberFormat('de-CH', {
+      style: 'currency',
+      currency: 'CHF'
+    }).format(amount);
+  };
+  
+  const getBillingModelLabel = (model: string) => {
+    switch (model) {
+      case 'PREPAY_MANDATE': return 'Prepaid (Mandant)';
+      case 'PREPAY_USER': return 'Prepaid (Benutzer)';
+      case 'CREDIT_POSTPAY': return 'Kredit';
+      case 'UNLIMITED': return 'Unlimited';
+      default: return model;
+    }
+  };
+  
+  return (
+    <div className={`${styles.balanceCard} ${balance.isWarning ? styles.warning : ''}`}>
+      <div className={styles.balanceHeader}>
+        <h3 className={styles.mandateName}>{balance.mandateName}</h3>
+        <span className={styles.billingModel}>{getBillingModelLabel(balance.billingModel)}</span>
+      </div>
+      <div className={styles.balanceAmount}>
+        {formatCurrency(balance.balance)}
+      </div>
+      {balance.isWarning && (
+        <div className={styles.warningBadge}>
+          Niedriges Guthaben
+        </div>
+      )}
+    </div>
+  );
+};
+
+// ============================================================================
+// STATISTICS CHART COMPONENT
+// ============================================================================
+
+interface StatisticsChartProps {
+  statistics: UsageReport | null;
+  loading?: boolean;
+}
+
+const StatisticsChart: React.FC<StatisticsChartProps> = ({ statistics, loading }) => {
+  const formatCurrency = (amount: number) => {
+    return new Intl.NumberFormat('de-CH', {
+      style: 'currency',
+      currency: 'CHF'
+    }).format(amount);
+  };
+  
+  if (loading) {
+    return <div className={styles.loadingPlaceholder}>Lade Statistiken...</div>;
+  }
+  
+  if (!statistics) {
+    return <div className={styles.noData}>Keine Statistiken verfügbar</div>;
+  }
+  
+  const maxProviderCost = Math.max(...Object.values(statistics.costByProvider), 1);
+  
+  return (
+    <div className={styles.statisticsChart}>
+      <div className={styles.totalCost}>
+        <span className={styles.totalLabel}>Gesamtkosten</span>
+        <span className={styles.totalAmount}>{formatCurrency(statistics.totalCost)}</span>
+      </div>
+      
+      <div className={styles.chartSection}>
+        <h4>Kosten nach Anbieter</h4>
+        {Object.entries(statistics.costByProvider).length === 0 ? (
+          <div className={styles.noData}>Keine Daten</div>
+        ) : (
+          <div className={styles.barChart}>
+            {Object.entries(statistics.costByProvider).map(([provider, cost]) => (
+              <div key={provider} className={styles.barRow}>
+                <span className={styles.barLabel}>{provider}</span>
+                <div className={styles.barContainer}>
+                  <div 
+                    className={styles.bar}
+                    style={{ width: `${(cost / maxProviderCost) * 100}%` }}
+                  />
+                </div>
+                <span className={styles.barValue}>{formatCurrency(cost)}</span>
+              </div>
+            ))}
+          </div>
+        )}
+      </div>
+      
+      <div className={styles.chartSection}>
+        <h4>Kosten nach Feature</h4>
+        {Object.entries(statistics.costByFeature).length === 0 ? (
+          <div className={styles.noData}>Keine Daten</div>
+        ) : (
+          <div className={styles.featureList}>
+            {Object.entries(statistics.costByFeature).map(([feature, cost]) => (
+              <div key={feature} className={styles.featureRow}>
+                <span className={styles.featureLabel}>{feature}</span>
+                <span className={styles.featureValue}>{formatCurrency(cost)}</span>
+              </div>
+            ))}
+          </div>
+        )}
+      </div>
+    </div>
+  );
+};
+
+// ============================================================================
+// TAB NAVIGATION COMPONENT
+// ============================================================================
+
+type TabType = 'overview' | 'transactions';
+
+interface TabNavProps {
+  activeTab: TabType;
+  onTabChange: (tab: TabType) => void;
+}
+
+const TabNav: React.FC<TabNavProps> = ({ activeTab, onTabChange }) => {
+  const navLinkStyle = (isActive: boolean) => ({
+    padding: '8px 16px',
+    textDecoration: 'none',
+    borderRadius: '4px',
+    backgroundColor: isActive ? 'var(--color-primary, #3b82f6)' : 'transparent',
+    color: isActive ? 'white' : 'var(--color-text, #e0e0e0)',
+    fontWeight: isActive ? 600 : 400,
+    cursor: 'pointer',
+    border: 'none',
+    fontSize: '14px',
+  });
+
+  return (
+    <nav style={{
+      display: 'flex',
+      gap: '8px',
+      marginBottom: '24px',
+      borderBottom: '1px solid var(--color-border, #333)',
+      paddingBottom: '8px'
+    }}>
+      <button
+        onClick={() => onTabChange('overview')}
+        style={navLinkStyle(activeTab === 'overview')}
+      >
+        Übersicht
+      </button>
+      <button
+        onClick={() => onTabChange('transactions')}
+        style={navLinkStyle(activeTab === 'transactions')}
+      >
+        Transaktionen
+      </button>
+    </nav>
+  );
+};
+
+// ============================================================================
+// MAIN COMPONENT
+// ============================================================================
+
+export const BillingDataView: React.FC = () => {
+  const [activeTab, setActiveTab] = useState<TabType>('overview');
+  
+  // Dashboard state (for Overview tab)
+  const { 
+    balances, 
+    statistics, 
+    loading: dashboardLoading, 
+    loadStatistics 
+  } = useBilling();
+  const [selectedPeriod, setSelectedPeriod] = useState<'month' | 'year'>('month');
+  const [selectedYear, setSelectedYear] = useState(new Date().getFullYear());
+  const [selectedMonth, setSelectedMonth] = useState(new Date().getMonth() + 1);
+  
+  // Transactions state (for Transactions tab)
+  const [transactions, setTransactions] = useState<UserTransaction[]>([]);
+  const [transactionsLoading, setTransactionsLoading] = useState(false);
+  const [transactionsError, setTransactionsError] = useState<string | null>(null);
+
+  // Load statistics when period changes
+  useEffect(() => {
+    if (selectedPeriod === 'month') {
+      loadStatistics('month', selectedYear);
+    } else {
+      loadStatistics('year', selectedYear);
+    }
+  }, [selectedPeriod, selectedYear, loadStatistics]);
+
+  // Load transactions
+  const loadTransactions = useCallback(async () => {
+    try {
+      setTransactionsLoading(true);
+      setTransactionsError(null);
+      const response = await api.get('/api/billing/view/users/transactions', {
+        params: { limit: 500 }
+      });
+      setTransactions(response.data || []);
+    } catch (err: any) {
+      console.error('Failed to load transactions:', err);
+      setTransactionsError(err.response?.data?.detail || err.message || 'Fehler beim Laden der Transaktionen');
+    } finally {
+      setTransactionsLoading(false);
+    }
+  }, []);
+
+  // Load transactions when switching to transactions tab
+  useEffect(() => {
+    if (activeTab === 'transactions' && transactions.length === 0) {
+      loadTransactions();
+    }
+  }, [activeTab, transactions.length, loadTransactions]);
+
+  // Available years
+  const availableYears = useMemo(() => {
+    const current = new Date().getFullYear();
+    return [current, current - 1, current - 2];
+  }, []);
+
+  // Available months
+  const availableMonths = [
+    { value: 1, label: 'Januar' },
+    { value: 2, label: 'Februar' },
+    { value: 3, label: 'März' },
+    { value: 4, label: 'April' },
+    { value: 5, label: 'Mai' },
+    { value: 6, label: 'Juni' },
+    { value: 7, label: 'Juli' },
+    { value: 8, label: 'August' },
+    { value: 9, label: 'September' },
+    { value: 10, label: 'Oktober' },
+    { value: 11, label: 'November' },
+    { value: 12, label: 'Dezember' },
+  ];
+
+  // Transform transactions for table display
+  const tableData = useMemo(() => {
+    return transactions.map((t, index) => ({
+      _uniqueId: `${t.id}-${t.mandateId}-${index}`,
+      id: t.id,
+      createdAt: t.createdAt,
+      mandateId: t.mandateId,
+      mandateName: t.mandateName || '-',
+      userId: t.userId,
+      userName: t.userName || '-',
+      transactionType: t.transactionType,
+      description: t.description || '-',
+      aicoreProvider: t.aicoreProvider || '-',
+      featureCode: t.featureCode || '-',
+      amount: t.transactionType === 'DEBIT' ? -t.amount : t.amount,
+    }));
+  }, [transactions]);
+
+  // Table column definitions
+  const columns: ColumnConfig[] = useMemo(() => [
+    {
+      key: 'createdAt',
+      label: 'Datum',
+      type: 'datetime',
+      sortable: true,
+      width: 160,
+    },
+    {
+      key: 'mandateName',
+      label: 'Mandant',
+      type: 'text',
+      sortable: true,
+      filterable: true,
+      searchable: true,
+      width: 150,
+    },
+    {
+      key: 'userName',
+      label: 'Benutzer',
+      type: 'text',
+      sortable: true,
+      filterable: true,
+      searchable: true,
+      width: 150,
+    },
+    {
+      key: 'transactionType',
+      label: 'Typ',
+      type: 'text',
+      sortable: true,
+      filterable: true,
+      filterOptions: ['CREDIT', 'DEBIT', 'ADJUSTMENT'],
+      width: 100,
+    },
+    {
+      key: 'description',
+      label: 'Beschreibung',
+      type: 'text',
+      searchable: true,
+      width: 250,
+    },
+    {
+      key: 'aicoreProvider',
+      label: 'Anbieter',
+      type: 'text',
+      sortable: true,
+      filterable: true,
+      width: 120,
+    },
+    {
+      key: 'featureCode',
+      label: 'Feature',
+      type: 'text',
+      sortable: true,
+      filterable: true,
+      width: 120,
+    },
+    {
+      key: 'amount',
+      label: 'Betrag (CHF)',
+      type: 'number',
+      sortable: true,
+      width: 120,
+    },
+  ], []);
+
+  return (
+    <div className={styles.billingDashboard}>
+      <header className={styles.pageHeader}>
+        <h1>Billing</h1>
+        <p className={styles.subtitle}>Guthaben, Statistiken und Transaktionen</p>
+      </header>
+
+      <TabNav activeTab={activeTab} onTabChange={setActiveTab} />
+
+      {/* Overview Tab */}
+      {activeTab === 'overview' && (
+        <>
+          {/* Balance Cards */}
+          <section className={styles.section}>
+            <h2 className={styles.sectionTitle}>Guthaben</h2>
+            {dashboardLoading ? (
+              <div className={styles.loadingPlaceholder}>Lade Guthaben...</div>
+            ) : balances.length === 0 ? (
+              <div className={styles.noData}>Keine Abrechnungskonten vorhanden</div>
+            ) : (
+              <div className={styles.balanceGrid}>
+                {balances.map((balance) => (
+                  <BalanceCard key={balance.mandateId} balance={balance} />
+                ))}
+              </div>
+            )}
+          </section>
+
+          {/* Statistics */}
+          <section className={styles.section}>
+            <div className={styles.sectionHeader}>
+              <h2 className={styles.sectionTitle}>Nutzungsstatistik</h2>
+              <div className={styles.periodSelector}>
+                <select 
+                  value={selectedPeriod} 
+                  onChange={(e) => setSelectedPeriod(e.target.value as 'month' | 'year')}
+                  className={styles.select}
+                >
+                  <option value="month">Monat</option>
+                  <option value="year">Jahr</option>
+                </select>
+                <select 
+                  value={selectedYear} 
+                  onChange={(e) => setSelectedYear(Number(e.target.value))}
+                  className={styles.select}
+                >
+                  {availableYears.map((year) => (
+                    <option key={year} value={year}>{year}</option>
+                  ))}
+                </select>
+                {selectedPeriod === 'month' && (
+                  <select 
+                    value={selectedMonth} 
+                    onChange={(e) => setSelectedMonth(Number(e.target.value))}
+                    className={styles.select}
+                  >
+                    {availableMonths.map((month) => (
+                      <option key={month.value} value={month.value}>{month.label}</option>
+                    ))}
+                  </select>
+                )}
+              </div>
+            </div>
+            <StatisticsChart statistics={statistics} loading={dashboardLoading} />
+          </section>
+        </>
+      )}
+
+      {/* Transactions Tab */}
+      {activeTab === 'transactions' && (
+        <>
+          {transactionsError && (
+            <div className={styles.errorMessage}>
+              {transactionsError}
+            </div>
+          )}
+
+          <FormGeneratorTable
+            data={tableData}
+            columns={columns}
+            loading={transactionsLoading}
+            pagination={true}
+            pageSize={25}
+            searchable={true}
+            filterable={true}
+            sortable={true}
+            idField="_uniqueId"
+            emptyMessage="Keine Transaktionen vorhanden"
+            onRefresh={loadTransactions}
+          />
+        </>
+      )}
+    </div>
+  );
+};
+
+export default BillingDataView;
diff --git a/src/pages/billing/BillingMandateView.tsx b/src/pages/billing/BillingMandateView.tsx
new file mode 100644
index 0000000..82d022f
--- /dev/null
+++ b/src/pages/billing/BillingMandateView.tsx
@@ -0,0 +1,280 @@
+/**
+ * Billing Mandate View Page
+ * 
+ * Shows mandate-level balances and transactions for SysAdmins.
+ * Includes filtering by mandate.
+ */
+
+import React, { useEffect, useState, useMemo } from 'react';
+import { useApiRequest } from '../../hooks/useApi';
+import {
+  fetchMandateViewBalances,
+  fetchMandateViewTransactions,
+  type MandateBalance,
+  type BillingTransaction
+} from '../../api/billingApi';
+import { BillingNav } from './BillingNav';
+import styles from './Billing.module.css';
+
+// ============================================================================
+// MANDATE BALANCE TABLE
+// ============================================================================
+
+interface MandateBalanceTableProps {
+  balances: MandateBalance[];
+  selectedMandateId: string | null;
+  onSelectMandate: (mandateId: string | null) => void;
+}
+
+const MandateBalanceTable: React.FC<MandateBalanceTableProps> = ({
+  balances,
+  selectedMandateId,
+  onSelectMandate
+}) => {
+  const formatCurrency = (amount: number) => {
+    return new Intl.NumberFormat('de-CH', {
+      style: 'currency',
+      currency: 'CHF'
+    }).format(amount);
+  };
+
+  const getBillingModelLabel = (model: string) => {
+    switch (model) {
+      case 'PREPAY_MANDATE': return 'Prepaid (Mandant)';
+      case 'PREPAY_USER': return 'Prepaid (Benutzer)';
+      case 'CREDIT_POSTPAY': return 'Kredit';
+      case 'UNLIMITED': return 'Unlimited';
+      default: return model;
+    }
+  };
+
+  return (
+    <div style={{ overflowX: 'auto' }}>
+      <table className={styles.transactionsTable}>
+        <thead>
+          <tr>
+            <th>Mandant</th>
+            <th>Billing-Modell</th>
+            <th>Anzahl Benutzer</th>
+            <th>Standard-Guthaben</th>
+            <th style={{ textAlign: 'right' }}>Gesamtguthaben</th>
+            <th>Aktion</th>
+          </tr>
+        </thead>
+        <tbody>
+          {balances.map((balance) => (
+            <tr 
+              key={balance.mandateId}
+              className={selectedMandateId === balance.mandateId ? styles.selectedRow : ''}
+            >
+              <td>{balance.mandateName || balance.mandateId}</td>
+              <td>{getBillingModelLabel(balance.billingModel)}</td>
+              <td>{balance.userCount}</td>
+              <td>{formatCurrency(balance.defaultUserCredit)}</td>
+              <td style={{ textAlign: 'right' }}>{formatCurrency(balance.totalBalance)}</td>
+              <td>
+                <button
+                  className={`${styles.button} ${styles.buttonSecondary}`}
+                  onClick={() => onSelectMandate(
+                    selectedMandateId === balance.mandateId ? null : balance.mandateId
+                  )}
+                  style={{ padding: '4px 8px', fontSize: '12px' }}
+                >
+                  {selectedMandateId === balance.mandateId ? 'Alle' : 'Filter'}
+                </button>
+              </td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
+    </div>
+  );
+};
+
+// ============================================================================
+// TRANSACTION TABLE
+// ============================================================================
+
+interface TransactionTableProps {
+  transactions: BillingTransaction[];
+}
+
+const TransactionTable: React.FC<TransactionTableProps> = ({ transactions }) => {
+  const formatCurrency = (amount: number) => {
+    return new Intl.NumberFormat('de-CH', {
+      style: 'currency',
+      currency: 'CHF'
+    }).format(amount);
+  };
+
+  const formatDate = (dateString?: string) => {
+    if (!dateString) return '-';
+    return new Date(dateString).toLocaleString('de-CH', {
+      year: 'numeric',
+      month: '2-digit',
+      day: '2-digit',
+      hour: '2-digit',
+      minute: '2-digit'
+    });
+  };
+
+  const getTypeClass = (type: string) => {
+    switch (type) {
+      case 'CREDIT': return styles.credit;
+      case 'DEBIT': return styles.debit;
+      case 'ADJUSTMENT': return styles.adjustment;
+      default: return '';
+    }
+  };
+
+  const getTypeLabel = (type: string) => {
+    switch (type) {
+      case 'CREDIT': return 'Gutschrift';
+      case 'DEBIT': return 'Belastung';
+      case 'ADJUSTMENT': return 'Korrektur';
+      default: return type;
+    }
+  };
+
+  return (
+    <div style={{ overflowX: 'auto' }}>
+      <table className={styles.transactionsTable}>
+        <thead>
+          <tr>
+            <th>Datum</th>
+            <th>Mandant</th>
+            <th>Typ</th>
+            <th>Beschreibung</th>
+            <th>Anbieter</th>
+            <th>Feature</th>
+            <th style={{ textAlign: 'right' }}>Betrag</th>
+          </tr>
+        </thead>
+        <tbody>
+          {transactions.map((t) => (
+            <tr key={t.id}>
+              <td>{formatDate(t.createdAt)}</td>
+              <td>{t.mandateName || '-'}</td>
+              <td>
+                <span className={`${styles.transactionType} ${getTypeClass(t.transactionType)}`}>
+                  {getTypeLabel(t.transactionType)}
+                </span>
+              </td>
+              <td>{t.description}</td>
+              <td>{t.aicoreProvider || '-'}</td>
+              <td>{t.featureCode || '-'}</td>
+              <td style={{ textAlign: 'right' }}>
+                {t.transactionType === 'DEBIT' ? '-' : '+'}{formatCurrency(t.amount)}
+              </td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
+    </div>
+  );
+};
+
+// ============================================================================
+// MAIN COMPONENT
+// ============================================================================
+
+export const BillingMandateView: React.FC = () => {
+  const { request, isLoading: loading } = useApiRequest();
+  const [balances, setBalances] = useState<MandateBalance[]>([]);
+  const [transactions, setTransactions] = useState<BillingTransaction[]>([]);
+  const [selectedMandateId, setSelectedMandateId] = useState<string | null>(null);
+  const [limit, setLimit] = useState(100);
+
+  // Load data
+  useEffect(() => {
+    const loadData = async () => {
+      try {
+        const [balanceData, transactionData] = await Promise.all([
+          fetchMandateViewBalances(request),
+          fetchMandateViewTransactions(request, limit)
+        ]);
+        setBalances(Array.isArray(balanceData) ? balanceData : []);
+        setTransactions(Array.isArray(transactionData) ? transactionData : []);
+      } catch (err) {
+        console.error('Error loading mandate view data:', err);
+        setBalances([]);
+        setTransactions([]);
+      }
+    };
+    loadData();
+  }, [request, limit]);
+
+  // Filter transactions by selected mandate
+  const filteredTransactions = useMemo(() => {
+    if (!selectedMandateId) return transactions;
+    return transactions.filter(t => t.mandateId === selectedMandateId);
+  }, [transactions, selectedMandateId]);
+
+  const handleLoadMore = () => {
+    setLimit(prev => prev + 100);
+  };
+
+  return (
+    <div className={styles.billingDashboard}>
+      <header className={styles.pageHeader}>
+        <h1>Mandanten-Billing</h1>
+        <p className={styles.subtitle}>Guthaben und Transaktionen pro Mandant</p>
+      </header>
+
+      <BillingNav />
+
+      {/* Mandate Balances */}
+      <section className={styles.section}>
+        <h2 className={styles.sectionTitle}>Mandanten-Guthaben</h2>
+        {loading && balances.length === 0 ? (
+          <div className={styles.loadingPlaceholder}>Lade Daten...</div>
+        ) : balances.length === 0 ? (
+          <div className={styles.noData}>Keine Mandanten mit Billing-Settings vorhanden</div>
+        ) : (
+          <MandateBalanceTable
+            balances={balances}
+            selectedMandateId={selectedMandateId}
+            onSelectMandate={setSelectedMandateId}
+          />
+        )}
+      </section>
+
+      {/* Transactions */}
+      <section className={styles.section}>
+        <div className={styles.sectionHeader}>
+          <h2 className={styles.sectionTitle}>
+            Transaktionen
+            {selectedMandateId && (
+              <span style={{ fontWeight: 'normal', fontSize: '14px', marginLeft: '8px' }}>
+                (gefiltert nach {balances.find(b => b.mandateId === selectedMandateId)?.mandateName || selectedMandateId})
+              </span>
+            )}
+          </h2>
+        </div>
+        {loading && transactions.length === 0 ? (
+          <div className={styles.loadingPlaceholder}>Lade Transaktionen...</div>
+        ) : filteredTransactions.length === 0 ? (
+          <div className={styles.noData}>Keine Transaktionen vorhanden</div>
+        ) : (
+          <>
+            <TransactionTable transactions={filteredTransactions} />
+            
+            {transactions.length >= limit && (
+              <div style={{ textAlign: 'center', marginTop: 'var(--spacing-md)' }}>
+                <button
+                  className={`${styles.button} ${styles.buttonSecondary}`}
+                  onClick={handleLoadMore}
+                  disabled={loading}
+                >
+                  {loading ? 'Laden...' : 'Mehr laden'}
+                </button>
+              </div>
+            )}
+          </>
+        )}
+      </section>
+    </div>
+  );
+};
+
+export default BillingMandateView;
diff --git a/src/pages/billing/BillingNav.tsx b/src/pages/billing/BillingNav.tsx
new file mode 100644
index 0000000..0b4c918
--- /dev/null
+++ b/src/pages/billing/BillingNav.tsx
@@ -0,0 +1,54 @@
+/**
+ * Billing Navigation Component
+ * 
+ * Provides navigation between billing views.
+ * Simplified: Übersicht (Dashboard) + Daten (FormGeneratorTable view)
+ */
+
+import React from 'react';
+import { NavLink } from 'react-router-dom';
+import styles from './Billing.module.css';
+
+export const BillingNav: React.FC = () => {
+  const navLinkStyle = (isActive: boolean) => ({
+    padding: '8px 16px',
+    textDecoration: 'none',
+    borderRadius: '4px',
+    backgroundColor: isActive ? 'var(--color-primary)' : 'transparent',
+    color: isActive ? 'white' : 'var(--color-text)',
+    fontWeight: isActive ? 600 : 400,
+  });
+
+  return (
+    <nav className={styles.billingNav} style={{
+      display: 'flex',
+      gap: '8px',
+      marginBottom: '24px',
+      borderBottom: '1px solid var(--color-border)',
+      paddingBottom: '8px'
+    }}>
+      <NavLink
+        to="/billing"
+        end
+        className={({ isActive }) => 
+          `${styles.navLink} ${isActive ? styles.navLinkActive : ''}`
+        }
+        style={({ isActive }) => navLinkStyle(isActive)}
+      >
+        Übersicht
+      </NavLink>
+      
+      <NavLink
+        to="/billing/transactions"
+        className={({ isActive }) => 
+          `${styles.navLink} ${isActive ? styles.navLinkActive : ''}`
+        }
+        style={({ isActive }) => navLinkStyle(isActive)}
+      >
+        Transaktionen
+      </NavLink>
+    </nav>
+  );
+};
+
+export default BillingNav;
diff --git a/src/pages/billing/BillingTransactions.tsx b/src/pages/billing/BillingTransactions.tsx
index f584bce..ddd7f2c 100644
--- a/src/pages/billing/BillingTransactions.tsx
+++ b/src/pages/billing/BillingTransactions.tsx
@@ -6,6 +6,7 @@
 
 import React, { useEffect, useState } from 'react';
 import { useBilling, type BillingTransaction } from '../../hooks/useBilling';
+import { BillingNav } from './BillingNav';
 import styles from './Billing.module.css';
 
 // ============================================================================
@@ -56,6 +57,7 @@ const TransactionRow: React.FC<TransactionRowProps> = ({ transaction }) => {
   return (
     <tr>
       <td>{formatDate(transaction.createdAt)}</td>
+      <td>{transaction.mandateName || '-'}</td>
       <td>
         <span className={`${styles.transactionType} ${getTypeClass(transaction.transactionType)}`}>
           {getTypeLabel(transaction.transactionType)}
@@ -94,6 +96,8 @@ export const BillingTransactions: React.FC = () => {
         <p className={styles.subtitle}>Übersicht aller Kontobewegungen</p>
       </header>
       
+      <BillingNav />
+      
       <section className={styles.section}>
         {loading && transactions.length === 0 ? (
           <div className={styles.loadingPlaceholder}>Lade Transaktionen...</div>
@@ -106,6 +110,7 @@ export const BillingTransactions: React.FC = () => {
                 <thead>
                   <tr>
                     <th>Datum</th>
+                    <th>Mandant</th>
                     <th>Typ</th>
                     <th>Beschreibung</th>
                     <th>Anbieter</th>
diff --git a/src/pages/billing/BillingUserView.tsx b/src/pages/billing/BillingUserView.tsx
new file mode 100644
index 0000000..194be7d
--- /dev/null
+++ b/src/pages/billing/BillingUserView.tsx
@@ -0,0 +1,376 @@
+/**
+ * Billing User View Page
+ * 
+ * Shows user-level balances and transactions.
+ * RBAC-based: Users see only their own data, Admins see all.
+ * Includes filtering by mandate and user.
+ */
+
+import React, { useEffect, useState, useMemo } from 'react';
+import { useApiRequest } from '../../hooks/useApi';
+import {
+  fetchUserViewBalances,
+  fetchUserViewTransactions,
+  type UserBalance,
+  type UserTransaction
+} from '../../api/billingApi';
+import { BillingNav } from './BillingNav';
+import styles from './Billing.module.css';
+
+// ============================================================================
+// USER BALANCE TABLE
+// ============================================================================
+
+interface UserBalanceTableProps {
+  balances: UserBalance[];
+  selectedMandateId: string | null;
+  selectedUserId: string | null;
+  onSelectMandate: (mandateId: string | null) => void;
+  onSelectUser: (userId: string | null) => void;
+}
+
+const UserBalanceTable: React.FC<UserBalanceTableProps> = ({
+  balances,
+  selectedMandateId,
+  selectedUserId,
+  onSelectMandate,
+  onSelectUser
+}) => {
+  const formatCurrency = (amount: number) => {
+    return new Intl.NumberFormat('de-CH', {
+      style: 'currency',
+      currency: 'CHF'
+    }).format(amount);
+  };
+
+  // Get unique mandates and users for filter dropdowns
+  const uniqueMandates = useMemo(() => {
+    const mandates = new Map<string, string>();
+    balances.forEach(b => {
+      if (b.mandateId && !mandates.has(b.mandateId)) {
+        mandates.set(b.mandateId, b.mandateName || b.mandateId);
+      }
+    });
+    return Array.from(mandates.entries());
+  }, [balances]);
+
+  const uniqueUsers = useMemo(() => {
+    const users = new Map<string, string>();
+    balances.forEach(b => {
+      if (b.userId && !users.has(b.userId)) {
+        users.set(b.userId, b.userName || b.userId);
+      }
+    });
+    return Array.from(users.entries());
+  }, [balances]);
+
+  // Apply filters
+  const filteredBalances = useMemo(() => {
+    let result = balances;
+    if (selectedMandateId) {
+      result = result.filter(b => b.mandateId === selectedMandateId);
+    }
+    if (selectedUserId) {
+      result = result.filter(b => b.userId === selectedUserId);
+    }
+    return result;
+  }, [balances, selectedMandateId, selectedUserId]);
+
+  return (
+    <>
+      {/* Filter Controls */}
+      <div className={styles.filterControls} style={{ display: 'flex', gap: '16px', marginBottom: '16px' }}>
+        <div>
+          <label style={{ display: 'block', marginBottom: '4px', fontSize: '12px', fontWeight: 500 }}>
+            Mandant:
+          </label>
+          <select
+            value={selectedMandateId || ''}
+            onChange={(e) => onSelectMandate(e.target.value || null)}
+            className={styles.select}
+          >
+            <option value="">Alle Mandanten</option>
+            {uniqueMandates.map(([id, name]) => (
+              <option key={id} value={id}>{name}</option>
+            ))}
+          </select>
+        </div>
+        <div>
+          <label style={{ display: 'block', marginBottom: '4px', fontSize: '12px', fontWeight: 500 }}>
+            Benutzer:
+          </label>
+          <select
+            value={selectedUserId || ''}
+            onChange={(e) => onSelectUser(e.target.value || null)}
+            className={styles.select}
+          >
+            <option value="">Alle Benutzer</option>
+            {uniqueUsers.map(([id, name]) => (
+              <option key={id} value={id}>{name}</option>
+            ))}
+          </select>
+        </div>
+      </div>
+
+      {/* Table */}
+      <div style={{ overflowX: 'auto' }}>
+        <table className={styles.transactionsTable}>
+          <thead>
+            <tr>
+              <th>Mandant</th>
+              <th>Benutzer</th>
+              <th style={{ textAlign: 'right' }}>Guthaben</th>
+              <th style={{ textAlign: 'right' }}>Warnschwelle</th>
+              <th>Status</th>
+            </tr>
+          </thead>
+          <tbody>
+            {filteredBalances.map((balance) => (
+              <tr 
+                key={balance.accountId}
+                className={balance.isWarning ? styles.warningRow : ''}
+              >
+                <td>{balance.mandateName || balance.mandateId}</td>
+                <td>{balance.userName || balance.userId}</td>
+                <td style={{ textAlign: 'right' }}>{formatCurrency(balance.balance)}</td>
+                <td style={{ textAlign: 'right' }}>{formatCurrency(balance.warningThreshold)}</td>
+                <td>
+                  {balance.isWarning ? (
+                    <span className={styles.warningBadge} style={{ fontSize: '12px', padding: '2px 6px' }}>
+                      Niedrig
+                    </span>
+                  ) : balance.enabled ? (
+                    <span style={{ color: 'var(--color-success)' }}>Aktiv</span>
+                  ) : (
+                    <span style={{ color: 'var(--color-error)' }}>Deaktiviert</span>
+                  )}
+                </td>
+              </tr>
+            ))}
+          </tbody>
+        </table>
+      </div>
+    </>
+  );
+};
+
+// ============================================================================
+// USER TRANSACTION TABLE
+// ============================================================================
+
+interface UserTransactionTableProps {
+  transactions: UserTransaction[];
+  selectedMandateId: string | null;
+  selectedUserId: string | null;
+}
+
+const UserTransactionTable: React.FC<UserTransactionTableProps> = ({
+  transactions,
+  selectedMandateId,
+  selectedUserId
+}) => {
+  const formatCurrency = (amount: number) => {
+    return new Intl.NumberFormat('de-CH', {
+      style: 'currency',
+      currency: 'CHF'
+    }).format(amount);
+  };
+
+  const formatDate = (dateString?: string) => {
+    if (!dateString) return '-';
+    return new Date(dateString).toLocaleString('de-CH', {
+      year: 'numeric',
+      month: '2-digit',
+      day: '2-digit',
+      hour: '2-digit',
+      minute: '2-digit'
+    });
+  };
+
+  const getTypeClass = (type: string) => {
+    switch (type) {
+      case 'CREDIT': return styles.credit;
+      case 'DEBIT': return styles.debit;
+      case 'ADJUSTMENT': return styles.adjustment;
+      default: return '';
+    }
+  };
+
+  const getTypeLabel = (type: string) => {
+    switch (type) {
+      case 'CREDIT': return 'Gutschrift';
+      case 'DEBIT': return 'Belastung';
+      case 'ADJUSTMENT': return 'Korrektur';
+      default: return type;
+    }
+  };
+
+  // Apply filters
+  const filteredTransactions = useMemo(() => {
+    let result = transactions;
+    if (selectedMandateId) {
+      result = result.filter(t => t.mandateId === selectedMandateId);
+    }
+    if (selectedUserId) {
+      result = result.filter(t => t.userId === selectedUserId);
+    }
+    return result;
+  }, [transactions, selectedMandateId, selectedUserId]);
+
+  return (
+    <div style={{ overflowX: 'auto' }}>
+      <table className={styles.transactionsTable}>
+        <thead>
+          <tr>
+            <th>Datum</th>
+            <th>Mandant</th>
+            <th>Benutzer</th>
+            <th>Typ</th>
+            <th>Beschreibung</th>
+            <th>Anbieter</th>
+            <th>Feature</th>
+            <th style={{ textAlign: 'right' }}>Betrag</th>
+          </tr>
+        </thead>
+        <tbody>
+          {filteredTransactions.map((t) => (
+            <tr key={t.id}>
+              <td>{formatDate(t.createdAt)}</td>
+              <td>{t.mandateName || '-'}</td>
+              <td>{t.userName || '-'}</td>
+              <td>
+                <span className={`${styles.transactionType} ${getTypeClass(t.transactionType)}`}>
+                  {getTypeLabel(t.transactionType)}
+                </span>
+              </td>
+              <td>{t.description}</td>
+              <td>{t.aicoreProvider || '-'}</td>
+              <td>{t.featureCode || '-'}</td>
+              <td style={{ textAlign: 'right' }}>
+                {t.transactionType === 'DEBIT' ? '-' : '+'}{formatCurrency(t.amount)}
+              </td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
+    </div>
+  );
+};
+
+// ============================================================================
+// MAIN COMPONENT
+// ============================================================================
+
+export const BillingUserView: React.FC = () => {
+  const { request, isLoading: loading } = useApiRequest();
+  const [balances, setBalances] = useState<UserBalance[]>([]);
+  const [transactions, setTransactions] = useState<UserTransaction[]>([]);
+  const [selectedMandateId, setSelectedMandateId] = useState<string | null>(null);
+  const [selectedUserId, setSelectedUserId] = useState<string | null>(null);
+  const [limit, setLimit] = useState(100);
+
+  // Load data
+  useEffect(() => {
+    const loadData = async () => {
+      try {
+        const [balanceData, transactionData] = await Promise.all([
+          fetchUserViewBalances(request),
+          fetchUserViewTransactions(request, limit)
+        ]);
+        setBalances(Array.isArray(balanceData) ? balanceData : []);
+        setTransactions(Array.isArray(transactionData) ? transactionData : []);
+      } catch (err) {
+        console.error('Error loading user view data:', err);
+        setBalances([]);
+        setTransactions([]);
+      }
+    };
+    loadData();
+  }, [request, limit]);
+
+  const handleLoadMore = () => {
+    setLimit(prev => prev + 100);
+  };
+
+  // Count filtered transactions for display
+  const filteredTransactionCount = useMemo(() => {
+    let result = transactions;
+    if (selectedMandateId) {
+      result = result.filter(t => t.mandateId === selectedMandateId);
+    }
+    if (selectedUserId) {
+      result = result.filter(t => t.userId === selectedUserId);
+    }
+    return result.length;
+  }, [transactions, selectedMandateId, selectedUserId]);
+
+  return (
+    <div className={styles.billingDashboard}>
+      <header className={styles.pageHeader}>
+        <h1>Benutzer-Billing</h1>
+        <p className={styles.subtitle}>Guthaben und Transaktionen pro Benutzer</p>
+      </header>
+
+      <BillingNav />
+
+      {/* User Balances */}
+      <section className={styles.section}>
+        <h2 className={styles.sectionTitle}>Benutzer-Guthaben</h2>
+        {loading && balances.length === 0 ? (
+          <div className={styles.loadingPlaceholder}>Lade Daten...</div>
+        ) : balances.length === 0 ? (
+          <div className={styles.noData}>Keine Benutzer-Konten vorhanden</div>
+        ) : (
+          <UserBalanceTable
+            balances={balances}
+            selectedMandateId={selectedMandateId}
+            selectedUserId={selectedUserId}
+            onSelectMandate={setSelectedMandateId}
+            onSelectUser={setSelectedUserId}
+          />
+        )}
+      </section>
+
+      {/* Transactions */}
+      <section className={styles.section}>
+        <div className={styles.sectionHeader}>
+          <h2 className={styles.sectionTitle}>
+            Transaktionen
+            {(selectedMandateId || selectedUserId) && (
+              <span style={{ fontWeight: 'normal', fontSize: '14px', marginLeft: '8px' }}>
+                ({filteredTransactionCount} gefiltert)
+              </span>
+            )}
+          </h2>
+        </div>
+        {loading && transactions.length === 0 ? (
+          <div className={styles.loadingPlaceholder}>Lade Transaktionen...</div>
+        ) : transactions.length === 0 ? (
+          <div className={styles.noData}>Keine Transaktionen vorhanden</div>
+        ) : (
+          <>
+            <UserTransactionTable
+              transactions={transactions}
+              selectedMandateId={selectedMandateId}
+              selectedUserId={selectedUserId}
+            />
+            
+            {transactions.length >= limit && (
+              <div style={{ textAlign: 'center', marginTop: 'var(--spacing-md)' }}>
+                <button
+                  className={`${styles.button} ${styles.buttonSecondary}`}
+                  onClick={handleLoadMore}
+                  disabled={loading}
+                >
+                  {loading ? 'Laden...' : 'Mehr laden'}
+                </button>
+              </div>
+            )}
+          </>
+        )}
+      </section>
+    </div>
+  );
+};
+
+export default BillingUserView;
diff --git a/src/pages/billing/index.ts b/src/pages/billing/index.ts
index eb4f6c7..86d7563 100644
--- a/src/pages/billing/index.ts
+++ b/src/pages/billing/index.ts
@@ -3,5 +3,11 @@
  */
 
 export { BillingDashboard } from './BillingDashboard';
-export { BillingTransactions } from './BillingTransactions';
+export { BillingDataView } from './BillingDataView';
 export { BillingAdmin } from './BillingAdmin';
+export { BillingNav } from './BillingNav';
+
+// Legacy exports (can be removed after migration)
+export { BillingTransactions } from './BillingTransactions';
+export { BillingMandateView } from './BillingMandateView';
+export { BillingUserView } from './BillingUserView';
diff --git a/src/pages/workflows/PlaygroundPage.module.css b/src/pages/workflows/PlaygroundPage.module.css
index cbb271b..32e8025 100644
--- a/src/pages/workflows/PlaygroundPage.module.css
+++ b/src/pages/workflows/PlaygroundPage.module.css
@@ -20,11 +20,24 @@
   flex-shrink: 0;
   display: flex;
   justify-content: space-between;
-  align-items: center;
+  align-items: flex-start;
   padding-bottom: 0.5rem;
   border-bottom: 1px solid var(--border-color);
 }
 
+.headerLeft {
+  display: flex;
+  flex-direction: column;
+  gap: 0.125rem;
+}
+
+.headerTitleRow {
+  display: flex;
+  align-items: center;
+  gap: 1rem;
+  flex-wrap: wrap;
+}
+
 .pageTitle {
   font-size: 1.5rem;
   font-weight: 600;
@@ -32,6 +45,24 @@
   margin: 0;
 }
 
+.headerStats {
+  display: flex;
+  align-items: center;
+  gap: 0.75rem;
+  font-size: 0.75rem;
+  color: var(--text-secondary);
+  background-color: var(--bg-secondary);
+  padding: 0.25rem 0.75rem;
+  border-radius: 12px;
+}
+
+.headerStatItem {
+  display: flex;
+  align-items: center;
+  gap: 0.25rem;
+  white-space: nowrap;
+}
+
 .pageSubtitle {
   font-size: 0.875rem;
   color: var(--text-secondary);
@@ -372,30 +403,6 @@
   border-color: var(--primary-color, #f25843);
 }
 
-/* Statistics bar */
-.statsBar {
-  display: flex;
-  gap: 1.5rem;
-  padding: 0.5rem 0;
-  font-size: 0.75rem;
-  color: var(--text-secondary);
-}
-
-.statItem {
-  display: flex;
-  align-items: center;
-  gap: 0.25rem;
-}
-
-.statLabel {
-  color: var(--text-tertiary);
-}
-
-.statValue {
-  font-weight: 500;
-  color: var(--text-secondary);
-}
-
 /* Pending files */
 .pendingFiles {
   display: flex;
diff --git a/src/pages/workflows/PlaygroundPage.tsx b/src/pages/workflows/PlaygroundPage.tsx
index 0733329..9dc6af7 100644
--- a/src/pages/workflows/PlaygroundPage.tsx
+++ b/src/pages/workflows/PlaygroundPage.tsx
@@ -582,8 +582,26 @@ export const PlaygroundPage: React.FC = () => {
 
             {/* Page Header */}
             <header className={styles.pageHeader}>
-                <div>
-                    <h1 className={styles.pageTitle}>Chat Playground</h1>
+                <div className={styles.headerLeft}>
+                    <div className={styles.headerTitleRow}>
+                        <h1 className={styles.pageTitle}>Chat Playground</h1>
+                        {/* Stats display in header */}
+                        <div className={styles.headerStats}>
+                            <span className={styles.headerStatItem} title="Daten gesendet / empfangen">
+                                ↑ {formatBytes(latestStats?.bytesSent || 0)} / ↓ {formatBytes(latestStats?.bytesReceived || 0)}
+                            </span>
+                            {(latestStats?.processingTime ?? 0) > 0 && (
+                                <span className={styles.headerStatItem} title="Verarbeitungszeit">
+                                    ⏱️ {formatDuration(latestStats?.processingTime || 0)}
+                                </span>
+                            )}
+                            {(latestStats?.priceUsd ?? 0) > 0 && (
+                                <span className={styles.headerStatItem} title="Kosten">
+                                    💰 CHF {(latestStats?.priceUsd || 0).toFixed(4)}
+                                </span>
+                            )}
+                        </div>
+                    </div>
                     <p className={styles.pageSubtitle}>Workflow-Ausführung und Chat-Interaktion</p>
                 </div>
                 <div className={styles.headerControls}>
@@ -711,36 +729,6 @@ export const PlaygroundPage: React.FC = () => {
                     </div>
                 )}
 
-                {/* Stats bar */}
-                {latestStats && (latestStats.bytesSent || latestStats.bytesReceived || latestStats.processingTime || latestStats.priceUsd) && (
-                    <div className={styles.statsBar}>
-                        {(latestStats.bytesSent !== undefined || latestStats.bytesReceived !== undefined) && (
-                            <div className={styles.statItem}>
-                                <span className={styles.statLabel}>Daten:</span>
-                                <span className={styles.statValue}>
-                                    {formatBytes(latestStats.bytesSent || 0)} / {formatBytes(latestStats.bytesReceived || 0)}
-                                </span>
-                            </div>
-                        )}
-                        {latestStats.processingTime !== undefined && latestStats.processingTime > 0 && (
-                            <div className={styles.statItem}>
-                                <span className={styles.statLabel}>Zeit:</span>
-                                <span className={styles.statValue}>
-                                    {formatDuration(latestStats.processingTime)}
-                                </span>
-                            </div>
-                        )}
-                        {latestStats.priceUsd !== undefined && latestStats.priceUsd > 0 && (
-                            <div className={styles.statItem}>
-                                <span className={styles.statLabel}>Kosten:</span>
-                                <span className={styles.statValue}>
-                                    ${latestStats.priceUsd.toFixed(4)}
-                                </span>
-                            </div>
-                        )}
-                    </div>
-                )}
-
                 {/* Input row */}
                 <div className={styles.inputRow}>
                     <div className={styles.inputWrapper}>
diff --git a/src/pages/workflows/WorkflowsPage.tsx b/src/pages/workflows/WorkflowsPage.tsx
index 2816cc0..a17060c 100644
--- a/src/pages/workflows/WorkflowsPage.tsx
+++ b/src/pages/workflows/WorkflowsPage.tsx
@@ -82,9 +82,11 @@ export const WorkflowsPage: React.FC = () => {
     }
   };
 
-  // Handle continue workflow - navigate to playground
+  // Handle continue workflow - navigate to playground within same feature instance
+  // Uses relative navigation since WorkflowsPage is rendered under same instance route as playground
   const handleContinueWorkflow = (workflow: Workflow) => {
-    navigate(`/workflows/playground?workflowId=${workflow.id}`);
+    // Navigate relatively to playground (sibling route under same instance)
+    navigate(`../playground?workflowId=${workflow.id}`);
   };
 
   // Handle edit submit