diff --git a/src/pages/Admin/UserManagement/rbacMocks.ts b/src/pages/Admin/UserManagement/rbacMocks.ts
new file mode 100644
index 0000000..083d1e8
--- /dev/null
+++ b/src/pages/Admin/UserManagement/rbacMocks.ts
@@ -0,0 +1,134 @@
+export interface MockUser {
+  id: string
+  username: string
+  displayName: string
+  email: string
+  provider: 'local' | 'oidc'
+  createdAt: string
+  directRoles: string[]
+  directGroups: string[]
+}
+
+export interface MockGroup {
+  id: string
+  name: string
+  parentId: string | null
+  builtIn: boolean
+  directRoles: string[]
+  memberUserIds: string[]
+}
+
+export interface MockRole {
+  id: string
+  name: string
+  description: string
+  scope: 'system' | 'custom'
+  system: boolean
+}
+
+export const MOCK_ROLES: MockRole[] = [
+  { id: 'role-1', name: 'ADMIN', description: 'Full system access', scope: 'system', system: true },
+  { id: 'role-2', name: 'USER', description: 'Standard user access', scope: 'system', system: true },
+  { id: 'role-3', name: 'EDITOR', description: 'Can modify routes and configurations', scope: 'custom', system: false },
+  { id: 'role-4', name: 'VIEWER', description: 'Read-only access to all resources', scope: 'custom', system: false },
+  { id: 'role-5', name: 'OPERATOR', description: 'Pipeline operator — start, stop, monitor', scope: 'custom', system: false },
+  { id: 'role-6', name: 'AUDITOR', description: 'Access to audit logs and compliance data', scope: 'custom', system: false },
+]
+
+export const MOCK_GROUPS: MockGroup[] = [
+  { id: 'grp-1', name: 'ADMINS', parentId: null, builtIn: true, directRoles: ['ADMIN'], memberUserIds: ['usr-1'] },
+  { id: 'grp-2', name: 'Developers', parentId: null, builtIn: false, directRoles: ['EDITOR'], memberUserIds: ['usr-2', 'usr-3'] },
+  { id: 'grp-3', name: 'Frontend', parentId: 'grp-2', builtIn: false, directRoles: ['VIEWER'], memberUserIds: ['usr-4'] },
+  { id: 'grp-4', name: 'Operations', parentId: null, builtIn: false, directRoles: ['OPERATOR', 'VIEWER'], memberUserIds: ['usr-5', 'usr-6'] },
+]
+
+export const MOCK_USERS: MockUser[] = [
+  {
+    id: 'usr-1', username: 'hendrik', displayName: 'Hendrik Siegeln',
+    email: 'hendrik@example.com', provider: 'local', createdAt: '2025-01-15T10:00:00Z',
+    directRoles: ['ADMIN'], directGroups: ['grp-1'],
+  },
+  {
+    id: 'usr-2', username: 'alice', displayName: 'Alice Johnson',
+    email: 'alice@example.com', provider: 'oidc', createdAt: '2025-03-20T14:30:00Z',
+    directRoles: ['VIEWER'], directGroups: ['grp-2'],
+  },
+  {
+    id: 'usr-3', username: 'bob', displayName: 'Bob Smith',
+    email: 'bob@example.com', provider: 'local', createdAt: '2025-04-10T09:00:00Z',
+    directRoles: [], directGroups: ['grp-2'],
+  },
+  {
+    id: 'usr-4', username: 'carol', displayName: 'Carol Davis',
+    email: 'carol@example.com', provider: 'oidc', createdAt: '2025-06-01T11:15:00Z',
+    directRoles: [], directGroups: ['grp-3'],
+  },
+  {
+    id: 'usr-5', username: 'dave', displayName: 'Dave Wilson',
+    email: 'dave@example.com', provider: 'local', createdAt: '2025-07-22T16:45:00Z',
+    directRoles: ['AUDITOR'], directGroups: ['grp-4'],
+  },
+  {
+    id: 'usr-6', username: 'eve', displayName: 'Eve Martinez',
+    email: 'eve@example.com', provider: 'oidc', createdAt: '2025-09-05T08:20:00Z',
+    directRoles: [], directGroups: ['grp-4'],
+  },
+  {
+    id: 'usr-7', username: 'frank', displayName: 'Frank Brown',
+    email: 'frank@example.com', provider: 'local', createdAt: '2025-11-12T13:00:00Z',
+    directRoles: ['USER'], directGroups: [],
+  },
+  {
+    id: 'usr-8', username: 'grace', displayName: 'Grace Lee',
+    email: 'grace@example.com', provider: 'oidc', createdAt: '2026-01-08T10:30:00Z',
+    directRoles: ['VIEWER', 'AUDITOR'], directGroups: [],
+  },
+]
+
+/** Resolve all roles for a user, including those inherited from groups */
+export function getEffectiveRoles(user: MockUser): Array<{ role: string; source: 'direct' | string }> {
+  const result: Array<{ role: string; source: 'direct' | string }> = []
+  const seen = new Set<string>()
+
+  // Direct roles
+  for (const role of user.directRoles) {
+    result.push({ role, source: 'direct' })
+    seen.add(role)
+  }
+
+  // Walk group chain for inherited roles
+  function walkGroup(groupId: string) {
+    const group = MOCK_GROUPS.find((g) => g.id === groupId)
+    if (!group) return
+    for (const role of group.directRoles) {
+      if (!seen.has(role)) {
+        result.push({ role, source: group.name })
+        seen.add(role)
+      }
+    }
+    // Walk parent group
+    if (group.parentId) walkGroup(group.parentId)
+  }
+
+  for (const groupId of user.directGroups) {
+    walkGroup(groupId)
+  }
+
+  return result
+}
+
+/** Get all groups in the chain (self + ancestors) for display */
+export function getGroupChain(groupId: string): MockGroup[] {
+  const chain: MockGroup[] = []
+  let current = MOCK_GROUPS.find((g) => g.id === groupId)
+  while (current) {
+    chain.unshift(current)
+    current = current.parentId ? MOCK_GROUPS.find((g) => g.id === current!.parentId) : undefined
+  }
+  return chain
+}
+
+/** Get child groups of a given group */
+export function getChildGroups(groupId: string): MockGroup[] {
+  return MOCK_GROUPS.filter((g) => g.parentId === groupId)
+}