diff --git a/packages/app-shell/src/console/AppContent.tsx b/packages/app-shell/src/console/AppContent.tsx
index 987e5cc73..1220d58ca 100644
--- a/packages/app-shell/src/console/AppContent.tsx
+++ b/packages/app-shell/src/console/AppContent.tsx
@@ -25,6 +25,7 @@ import { PreviewDraftEmptyState } from '../preview/PreviewDraftEmptyState';
 import { ExpressionProvider, evaluateVisibility } from '../providers/ExpressionProvider';
 import { useTrackRouteAsRecent } from '../hooks/useTrackRouteAsRecent';
 import { resolveRecordFormTarget, resolveNavigateCreateUrl, resolveNavigateEditUrl } from '../utils/recordFormNavigation';
+import { matchAppBySegment } from '../utils/appRoute';
 import { resolveHref, type NavTemplateContext } from '@object-ui/layout';
 import { ExpressionEvaluator } from '@object-ui/core';
 
@@ -172,7 +173,9 @@ export function AppContent({ extraRoutes, extraRoutesNoApp }: AppContentProps =
   const activeApps = apps.filter((a: any) => a.active !== false);
   const launcherApps = activeApps.filter((a: any) => a.hidden !== true);
   const activeApp =
-    apps.find((a: any) => a.name === appName) ||
+    // ADR-0048 (A) — the route segment is the package id; resolve by it,
+    // falling back to the app name (legacy/alias URL).
+    matchAppBySegment(apps, appName) ||
     launcherApps.find((a: any) => a.isDefault === true) ||
     launcherApps[0];
 
diff --git a/packages/app-shell/src/hooks/useNavigationSync.ts b/packages/app-shell/src/hooks/useNavigationSync.ts
index d4f4ffba5..1377f3ddb 100644
--- a/packages/app-shell/src/hooks/useNavigationSync.ts
+++ b/packages/app-shell/src/hooks/useNavigationSync.ts
@@ -15,6 +15,7 @@ import type { NavigationItem, AppSchema } from '@object-ui/types';
 import { useObjectTranslation } from '@object-ui/i18n';
 import { useAdapter } from '../providers/AdapterProvider';
 import { useMetadata } from '../providers/MetadataProvider';
+import { matchAppBySegment } from '../utils/appRoute';
 import { usePreviewDrafts } from '../preview/PreviewModeContext';
 
 // ============================================================================
@@ -222,7 +223,7 @@ export function useNavigationSync(): UseNavigationSyncReturn {
   /** Find the current app schema from metadata by name. */
   const findApp = useCallback(
     (appName: string): AppSchema | undefined =>
-      apps.find((a: any) => a.name === appName) as AppSchema | undefined,
+      matchAppBySegment(apps, appName) as AppSchema | undefined,
     [apps],
   );
 
diff --git a/packages/app-shell/src/layout/AppHeader.tsx b/packages/app-shell/src/layout/AppHeader.tsx
index 915d5b6a2..59c483b6b 100644
--- a/packages/app-shell/src/layout/AppHeader.tsx
+++ b/packages/app-shell/src/layout/AppHeader.tsx
@@ -61,7 +61,7 @@ import { useObjectTranslation, useObjectLabel } from '@object-ui/i18n';
 import type { BreadcrumbItem as BreadcrumbItemType } from '@object-ui/types';
 import { useAuth, getUserInitials } from '@object-ui/auth';
 import { useMetadata } from '../providers/MetadataProvider';
-import { resolveI18nLabel, preferLocal } from '../utils';
+import { resolveI18nLabel, preferLocal, matchAppBySegment } from '../utils';
 import { getIcon } from '../utils/getIcon';
 import { useMobileViewSwitcher } from './MobileViewSwitcherContext';
 import { useNavigationContext } from '../context/NavigationContext';
@@ -457,7 +457,8 @@ export function AppHeader({
 
   // Filter objects to only those belonging to the current app via its navigation
   const appNameKey = activeAppName || currentAppName || appNameFromRoute;
-  const currentApp = (metadataApps || []).find((a: any) => a.name === appNameKey);
+  // ADR-0048 (A) — appNameKey may be a package id (route segment); match by it.
+  const currentApp = matchAppBySegment(metadataApps || [], appNameKey);
   const appNavObjectNames = new Set<string>();
   const collectNavObjects = (items: any[]) => {
     for (const item of items || []) {
diff --git a/packages/app-shell/src/layout/AppSidebar.tsx b/packages/app-shell/src/layout/AppSidebar.tsx
index ed8fbcffe..4ab7071cc 100644
--- a/packages/app-shell/src/layout/AppSidebar.tsx
+++ b/packages/app-shell/src/layout/AppSidebar.tsx
@@ -61,7 +61,7 @@ import { usePermissions } from '@object-ui/permissions';
 import { useRecentItems } from '../hooks/useRecentItems';
 import { useFavorites } from '../hooks/useFavorites';
 import { useNavPins } from '../hooks/useNavPins';
-import { resolveI18nLabel } from '../utils';
+import { resolveI18nLabel, matchAppBySegment } from '../utils';
 import { useObjectTranslation, useObjectLabel } from '@object-ui/i18n';
 import { useAppContextSelectors } from './ContextSelectors';
 
@@ -175,7 +175,8 @@ export function AppSidebar({ activeAppName, onAppChange }: { activeAppName: stri
   const activeApps = apps.filter((a: any) => a.active !== false && a.hidden !== true);
   // The active-app lookup still spans ALL apps (incl. hidden) so a
   // direct /apps/account navigation keeps rendering the Account branding.
-  const activeApp = apps.find((a: any) => a.name === activeAppName && a.active !== false) || activeApps[0];
+  // ADR-0048 (A) — route segment may be a package id; match by it (name fallback).
+  const activeApp = matchAppBySegment(apps.filter((a: any) => a.active !== false), activeAppName) || activeApps[0];
 
   // Extract branding information from spec
   const logo = activeApp?.branding?.logo;
diff --git a/packages/app-shell/src/layout/AppSwitcher.tsx b/packages/app-shell/src/layout/AppSwitcher.tsx
index 134c25fa7..a501b4043 100644
--- a/packages/app-shell/src/layout/AppSwitcher.tsx
+++ b/packages/app-shell/src/layout/AppSwitcher.tsx
@@ -17,7 +17,7 @@ import {
 } from '@object-ui/components';
 import { ChevronDown, Check } from 'lucide-react';
 import { useMetadata } from '../providers/MetadataProvider';
-import { resolveI18nLabel } from '../utils';
+import { resolveI18nLabel, matchAppBySegment } from '../utils';
 import { useObjectTranslation, useObjectLabel } from '@object-ui/i18n';
 import { getIcon } from '../utils/getIcon';
 
@@ -36,7 +36,8 @@ export function AppSwitcher({ activeAppName, onAppChange }: AppSwitcherProps) {
   // (personal-settings-style surfaces like the Account app), not the
   // top-level App Switcher.
   const activeApps = apps.filter((a: any) => a.active !== false && a.hidden !== true);
-  const activeApp = activeApps.find((a: any) => a.name === activeAppName) || apps.find((a: any) => a.name === activeAppName && a.active !== false) || activeApps[0];
+  // ADR-0048 (A) — route segment may be a package id; match by it (name fallback).
+  const activeApp = matchAppBySegment(activeApps, activeAppName) || matchAppBySegment(apps.filter((a: any) => a.active !== false), activeAppName) || activeApps[0];
 
   if (!activeApp) return null;
 
diff --git a/packages/app-shell/src/layout/UnifiedSidebar.tsx b/packages/app-shell/src/layout/UnifiedSidebar.tsx
index 469ffe5f0..582cfee42 100644
--- a/packages/app-shell/src/layout/UnifiedSidebar.tsx
+++ b/packages/app-shell/src/layout/UnifiedSidebar.tsx
@@ -47,7 +47,7 @@ import { useAuth, useIsWorkspaceAdmin } from '@object-ui/auth';
 import { useRecentItems } from '../hooks/useRecentItems';
 import { useFavorites } from '../hooks/useFavorites';
 import { useNavPins } from '../hooks/useNavPins';
-import { resolveI18nLabel } from '../utils';
+import { resolveI18nLabel, matchAppBySegment } from '../utils';
 import { useObjectTranslation, useObjectLabel } from '@object-ui/i18n';
 // useObjectLabel provides appLabel/appDescription for convention-based
 // i18n lookup — `{ns}.apps.{name}.label` resolves to the translated label
@@ -183,7 +183,8 @@ export function UnifiedSidebar({ activeAppName }: UnifiedSidebarProps) {
   // Filter switcher to non-hidden apps; active-app lookup spans all so
   // direct navigation to /apps/account still renders.
   const activeApps = apps.filter((a: any) => a.active !== false && a.hidden !== true);
-  const activeApp = apps.find((a: any) => a.name === (activeAppName || currentAppName) && a.active !== false) || activeApps[0];
+  // ADR-0048 (A) — route segment may be a package id; match by it (name fallback).
+  const activeApp = matchAppBySegment(apps.filter((a: any) => a.active !== false), activeAppName || currentAppName) || activeApps[0];
 
   // Drag-reorder and pin persistence
   const { applyOrder, handleReorder } = useNavOrder(activeApp?.name || 'home');
diff --git a/packages/app-shell/src/preview/UnpublishedAppBar.tsx b/packages/app-shell/src/preview/UnpublishedAppBar.tsx
index 8524c3e97..fd98e0bad 100644
--- a/packages/app-shell/src/preview/UnpublishedAppBar.tsx
+++ b/packages/app-shell/src/preview/UnpublishedAppBar.tsx
@@ -26,6 +26,7 @@ import { toast } from 'sonner';
 import { Button } from '@object-ui/components';
 import { useObjectTranslation } from '@object-ui/i18n';
 import { useMetadata } from '../providers/MetadataProvider';
+import { matchAppBySegment } from '../utils/appRoute';
 import { usePreviewDrafts } from './PreviewModeContext';
 
 export function UnpublishedAppBar() {
@@ -40,7 +41,7 @@ export function UnpublishedAppBar() {
   if (preview) return null;
   const routeApp = appName ?? location.pathname.match(/\/apps\/([^/?#]+)/)?.[1];
   if (!routeApp) return null;
-  const app = (apps ?? []).find((a: any) => a?.name === routeApp);
+  const app = matchAppBySegment(apps ?? [], routeApp);
   if (!app || (app as any).hidden !== true) return null;
 
   const publish = async () => {
diff --git a/packages/app-shell/src/utils/__tests__/appRoute.test.ts b/packages/app-shell/src/utils/__tests__/appRoute.test.ts
new file mode 100644
index 000000000..5734f1f33
--- /dev/null
+++ b/packages/app-shell/src/utils/__tests__/appRoute.test.ts
@@ -0,0 +1,40 @@
+import { describe, it, expect } from 'vitest';
+import { appRouteSegment, matchAppBySegment } from '../appRoute';
+
+/**
+ * ADR-0048 (option A) — package-id route segment.
+ */
+describe('appRouteSegment', () => {
+  it('returns the package id when present', () => {
+    expect(appRouteSegment({ name: 'crm', _packageId: 'com.acme.crm' })).toBe('com.acme.crm');
+  });
+  it('falls back to the app name when no package id', () => {
+    expect(appRouteSegment({ name: 'crm' })).toBe('crm');
+  });
+  it('returns undefined for nullish input', () => {
+    expect(appRouteSegment(undefined)).toBeUndefined();
+    expect(appRouteSegment(null)).toBeUndefined();
+  });
+});
+
+describe('matchAppBySegment', () => {
+  const crm = { name: 'crm', _packageId: 'com.acme.crm' };
+  const hr = { name: 'crm', _packageId: 'com.beta.crm' }; // same display name, different vendor
+  const apps = [crm, hr];
+
+  it('matches by package id (disambiguates same-named apps)', () => {
+    expect(matchAppBySegment(apps, 'com.acme.crm')).toBe(crm);
+    expect(matchAppBySegment(apps, 'com.beta.crm')).toBe(hr);
+  });
+  it('falls back to matching by name (legacy/alias URL)', () => {
+    expect(matchAppBySegment([{ name: 'sales' }], 'sales')).toEqual({ name: 'sales' });
+  });
+  it('prefers a package-id match over a name match', () => {
+    const byName = { name: 'com.acme.crm' }; // pathological: an app literally named like a pkg id
+    expect(matchAppBySegment([byName, crm], 'com.acme.crm')).toBe(crm);
+  });
+  it('returns undefined for missing inputs', () => {
+    expect(matchAppBySegment(apps, undefined)).toBeUndefined();
+    expect(matchAppBySegment(null, 'com.acme.crm')).toBeUndefined();
+  });
+});
diff --git a/packages/app-shell/src/utils/appRoute.ts b/packages/app-shell/src/utils/appRoute.ts
new file mode 100644
index 000000000..d26faebb3
--- /dev/null
+++ b/packages/app-shell/src/utils/appRoute.ts
@@ -0,0 +1,30 @@
+/**
+ * ADR-0048 (option A) — the `/apps/<segment>` route is keyed on the **package
+ * id** (reverse-domain, globally unique), not the app's display name. This makes
+ * two vendors' same-named apps unambiguous and self-describing in the URL.
+ *
+ * - `appRouteSegment(app)` — the canonical route segment for linking TO an app
+ *   (its package id; falls back to `name` for runtime/DB apps with no
+ *   `_packageId`).
+ * - `matchAppBySegment(apps, seg)` — resolve a route segment back to its app,
+ *   preferring the package id and falling back to the app name. The name
+ *   fallback doubles as a per-tenant friendly alias and keeps legacy
+ *   name-based URLs/bookmarks working. Callers keep their own
+ *   default/first-app fallback around this match.
+ */
+
+type AppLike = { name?: unknown; _packageId?: unknown } & Record<string, unknown>;
+
+export function appRouteSegment(app: AppLike | null | undefined): string | undefined {
+  if (!app) return undefined;
+  const seg = (app._packageId as string | undefined) ?? (app.name as string | undefined);
+  return seg ?? undefined;
+}
+
+export function matchAppBySegment<T extends AppLike>(
+  apps: readonly T[] | null | undefined,
+  seg: string | null | undefined,
+): T | undefined {
+  if (!apps || seg == null) return undefined;
+  return apps.find((a) => a?._packageId === seg) ?? apps.find((a) => a?.name === seg);
+}
diff --git a/packages/app-shell/src/utils/index.ts b/packages/app-shell/src/utils/index.ts
index ac6dc5806..15741bca1 100644
--- a/packages/app-shell/src/utils/index.ts
+++ b/packages/app-shell/src/utils/index.ts
@@ -14,6 +14,7 @@ export { deriveRelatedLists } from './deriveRelatedLists';
 export type { DerivedRelatedList } from './deriveRelatedLists';
 
 export { preferLocal } from './preferLocal';
+export { appRouteSegment, matchAppBySegment } from './appRoute';
 
 /**
  * Resolves an I18nLabel to a plain string.
diff --git a/packages/app-shell/src/views/SearchResultsPage.tsx b/packages/app-shell/src/views/SearchResultsPage.tsx
index 1e3989eed..c75ba4e59 100644
--- a/packages/app-shell/src/views/SearchResultsPage.tsx
+++ b/packages/app-shell/src/views/SearchResultsPage.tsx
@@ -25,6 +25,7 @@ import {
 } from 'lucide-react';
 import { useObjectTranslation } from '@object-ui/i18n';
 import { useMetadata } from '../providers/MetadataProvider';
+import { matchAppBySegment } from '../utils/appRoute';
 import { resolveHref } from '@object-ui/layout';
 import { useAuth } from '@object-ui/auth';
 
@@ -72,7 +73,7 @@ export function SearchResultsPage() {
 
   const { apps: metadataApps } = useMetadata();
   const apps = metadataApps || [];
-  const activeApp = apps.find((a: any) => a.name === appName) || apps[0];
+  const activeApp = matchAppBySegment(apps, appName) || apps[0];
   const baseUrl = `/apps/${appName}`;
   const { user } = useAuth();