diff --git a/apps/mobile/android/app/build.gradle b/apps/mobile/android/app/build.gradle
index 40b74821..41cbd245 100644
--- a/apps/mobile/android/app/build.gradle
+++ b/apps/mobile/android/app/build.gradle
@@ -22,7 +22,7 @@ react {
     //   skip the bundling of the JS bundle and the assets. Default is "debug", "debugOptimized".
     //   If you add flavors like lite, prod, etc. you'll have to list your debuggableVariants.
     // debuggableVariants = ["liteDebug", "liteDebugOptimized", "prodDebug", "prodDebugOptimized"]
-
+    debuggableVariants = ["debug"]
     /* Bundling */
     //   A list containing the node command and its flags. Default is just 'node'.
     // nodeExecutableAndArgs = ["node"]
diff --git a/apps/mobile/android/app/src/main/java/com/devcard/app/MainApplication.kt b/apps/mobile/android/app/src/main/java/com/devcard/app/MainApplication.kt
index a7b8f9f2..a8bffaa8 100644
--- a/apps/mobile/android/app/src/main/java/com/devcard/app/MainApplication.kt
+++ b/apps/mobile/android/app/src/main/java/com/devcard/app/MainApplication.kt
@@ -4,24 +4,34 @@ import android.app.Application
 import com.facebook.react.PackageList
 import com.facebook.react.ReactApplication
 import com.facebook.react.ReactHost
-import com.facebook.react.ReactNativeApplicationEntryPoint.loadReactNative
+import com.facebook.react.ReactNativeHost
+import com.facebook.react.ReactPackage
 import com.facebook.react.defaults.DefaultReactHost.getDefaultReactHost
+import com.facebook.react.defaults.DefaultReactNativeHost
+import com.facebook.react.ReactNativeApplicationEntryPoint.loadReactNative
 
 class MainApplication : Application(), ReactApplication {
 
-  override val reactHost: ReactHost by lazy {
-    getDefaultReactHost(
-      context = applicationContext,
-      packageList =
-        PackageList(this).packages.apply {
-          // Packages that cannot be autolinked yet can be added manually here, for example:
-          // add(MyReactNativePackage())
-        },
-    )
-  }
+  override val reactNativeHost: ReactNativeHost =
+    object : DefaultReactNativeHost(this) {
+
+      override fun getPackages(): List<ReactPackage> =
+        PackageList(this).packages
+
+      override fun getJSMainModuleName(): String = "index"
+
+      override fun getUseDeveloperSupport(): Boolean = BuildConfig.DEBUG
+
+      override val isNewArchEnabled: Boolean = BuildConfig.IS_NEW_ARCHITECTURE_ENABLED
+      override val isHermesEnabled: Boolean = BuildConfig.IS_HERMES_ENABLED
+    }
+
+  override val reactHost: ReactHost
+    get() = getDefaultReactHost(applicationContext, reactNativeHost)
 
   override fun onCreate() {
     super.onCreate()
     loadReactNative(this)
   }
 }
+
diff --git a/apps/mobile/src/config.ts b/apps/mobile/src/config.ts
index 3ef038e2..9b7e374f 100644
--- a/apps/mobile/src/config.ts
+++ b/apps/mobile/src/config.ts
@@ -12,6 +12,12 @@ export const API_BASE_URL: string = __DEV__
   ? `http://${DEV_HOST}:3000`
   : 'https://api.devcard.dev';
 
+// OAuth must use the same host for start and callback so browser cookies/state match.
+// Android reaches the host machine via `adb reverse tcp:3000 tcp:3000`.
+export const AUTH_BASE_URL: string = __DEV__
+  ? 'http://localhost:3000'
+  : 'https://api.devcard.dev';
+
 export const APP_URL: string = __DEV__
   ? 'http://localhost:5173'
   : 'https://devcard.dev';
@@ -20,3 +26,9 @@ export const APP_URL: string = __DEV__
 export const DEEP_LINK_SCHEME = 'devcard';
 
 export const OAUTH_REDIRECT_URI = `${DEEP_LINK_SCHEME}://oauth/callback`;
+
+// Backend OAuth placeholders. Replace these once backend routes are finalized.
+export const BACKEND_AUTH_ROUTES = {
+  github: '/auth/github',
+  google: '/auth/google',
+} as const;
diff --git a/apps/mobile/src/services/backendAuth.ts b/apps/mobile/src/services/backendAuth.ts
new file mode 100644
index 00000000..5deb69b8
--- /dev/null
+++ b/apps/mobile/src/services/backendAuth.ts
@@ -0,0 +1,36 @@
+import { Linking } from 'react-native';
+import { AUTH_BASE_URL, BACKEND_AUTH_ROUTES, OAUTH_REDIRECT_URI } from '../config';
+
+type AuthProvider = keyof typeof BACKEND_AUTH_ROUTES;
+
+export function buildBackendAuthUrl(provider: AuthProvider) {
+  const route = BACKEND_AUTH_ROUTES[provider];
+  const params = new URLSearchParams({
+    client: 'mobile',
+    provider,
+    state: `mobile_${provider}`,
+    mobile_redirect_uri: OAUTH_REDIRECT_URI,
+  });
+
+  return `${AUTH_BASE_URL}${route}?${params.toString()}`;
+}
+
+export async function startBackendOAuth(provider: AuthProvider) {
+  const url = buildBackendAuthUrl(provider);
+  const canOpen = await Linking.canOpenURL(url);
+
+  if (!canOpen) {
+    throw new Error(`Cannot open auth URL for ${provider}.`);
+  }
+
+  await Linking.openURL(url);
+}
+
+export function getJwtFromCallbackUrl(url: string) {
+  if (!url.startsWith(OAUTH_REDIRECT_URI)) return null;
+
+  const queryString = url.includes('#') ? url.split('#')[1] : url.split('?')[1] || '';
+  const params = new URLSearchParams(queryString);
+
+  return params.get('token') || params.get('jwt') || params.get('access_token');
+}
diff --git a/packages/shared/src/__tests__/cards.test.ts b/packages/shared/src/__tests__/cards.test.ts
index 0c1a6d1e..20c3e52c 100644
--- a/packages/shared/src/__tests__/cards.test.ts
+++ b/packages/shared/src/__tests__/cards.test.ts
@@ -69,4 +69,4 @@ describe('diffCardPlatforms', () => {
     expect(diff.removed).toEqual([]);
     expect(diff.unchanged).toEqual(['github']);
   });
-});
\ No newline at end of file
+});
diff --git a/packages/shared/src/__tests__/platforms-url.test.ts b/packages/shared/src/__tests__/platforms-url.test.ts
index cbfac373..2ddb7c2d 100644
--- a/packages/shared/src/__tests__/platforms-url.test.ts
+++ b/packages/shared/src/__tests__/platforms-url.test.ts
@@ -1,8 +1,6 @@
 import { describe, it, expect } from 'vitest';
 import { getProfileUrl, getWebViewUrl, getDeepLinkUrl } from '../platforms';
 
-// ─── getProfileUrl Tests ───
-
 describe('getProfileUrl', () => {
   it('should return the correct GitHub profile URL', () => {
     expect(getProfileUrl('github', 'octocat')).toBe('https://github.com/octocat');
@@ -21,8 +19,6 @@ describe('getProfileUrl', () => {
   });
 });
 
-// ─── getWebViewUrl Tests ───
-
 describe('getWebViewUrl', () => {
   it('should return the correct LinkedIn webview URL', () => {
     expect(getWebViewUrl('linkedin', 'john')).toBe('https://www.linkedin.com/in/john');
@@ -41,8 +37,6 @@ describe('getWebViewUrl', () => {
   });
 });
 
-// ─── getDeepLinkUrl Tests ───
-
 describe('getDeepLinkUrl', () => {
   it('should return the correct Twitter deep link URL', () => {
     expect(getDeepLinkUrl('twitter', 'john')).toBe('twitter://user?screen_name=john');
diff --git a/packages/shared/src/cards.ts b/packages/shared/src/cards.ts
index d9fa5130..0405d7e5 100644
--- a/packages/shared/src/cards.ts
+++ b/packages/shared/src/cards.ts
@@ -47,4 +47,4 @@ export function diffCardPlatforms(
     removed: oldCard.filter(p => !newSet.has(p)),
     unchanged: oldCard.filter(p => newSet.has(p)),
   };
-}
\ No newline at end of file
+}
diff --git a/packages/shared/src/platforms.test.ts b/packages/shared/src/platforms.test.ts
index 6ce07a0b..73ce0e33 100644
--- a/packages/shared/src/platforms.test.ts
+++ b/packages/shared/src/platforms.test.ts
@@ -8,8 +8,6 @@ import {
   getDeepLinkUrl,
 } from './platforms';
 
-// ─── StackOverflow Platform Tests ───
-
 describe('stackoverflow platform', () => {
   it('should exist in PLATFORMS registry', () => {
     expect(PLATFORMS.stackoverflow).toBeDefined();
@@ -44,9 +42,7 @@ describe('stackoverflow platform', () => {
   });
 });
 
-// ─── getProfileUrl Tests for StackOverflow ───
-
-describe('getProfileUrl – stackoverflow', () => {
+describe('getProfileUrl - stackoverflow', () => {
   it('should generate correct URL with user ID and display name', () => {
     const url = getProfileUrl('stackoverflow', '1234/user');
     expect(url).toBe('https://stackoverflow.com/users/1234/user');
@@ -63,9 +59,7 @@ describe('getProfileUrl – stackoverflow', () => {
   });
 });
 
-// ─── getWebViewUrl / getDeepLinkUrl for StackOverflow ───
-
-describe('getWebViewUrl / getDeepLinkUrl – stackoverflow', () => {
+describe('getWebViewUrl / getDeepLinkUrl - stackoverflow', () => {
   it('should return null for webViewUrl (not supported)', () => {
     expect(getWebViewUrl('stackoverflow', '1234/user')).toBeNull();
   });
@@ -75,15 +69,12 @@ describe('getWebViewUrl / getDeepLinkUrl – stackoverflow', () => {
   });
 });
 
-// ─── validationRegex Tests ───
-
 describe('validationRegex logic', () => {
   it('should correctly validate github usernames', () => {
     const regex = PLATFORMS.github.validationRegex!;
     expect(regex.test('valid-user')).toBe(true);
     expect(regex.test('a')).toBe(true);
     expect(regex.test('user123')).toBe(true);
-    // Invalid
     expect(regex.test('-invalid')).toBe(false);
     expect(regex.test('invalid-')).toBe(false);
     expect(regex.test('in--valid')).toBe(false);
@@ -94,8 +85,7 @@ describe('validationRegex logic', () => {
     const regex = PLATFORMS.linkedin.validationRegex!;
     expect(regex.test('valid-user')).toBe(true);
     expect(regex.test('user123')).toBe(true);
-    // Invalid
-    expect(regex.test('ab')).toBe(false); // Too short
+    expect(regex.test('ab')).toBe(false);
     expect(regex.test('user name')).toBe(false);
   });
 
@@ -103,9 +93,8 @@ describe('validationRegex logic', () => {
     const regex = PLATFORMS.twitter.validationRegex!;
     expect(regex.test('valid_user')).toBe(true);
     expect(regex.test('user123')).toBe(true);
-    // Invalid
-    expect(regex.test('user-name')).toBe(false); // Hyphens not allowed
-    expect(regex.test('this_is_a_very_long_name_indeed')).toBe(false); // Too long
+    expect(regex.test('user-name')).toBe(false);
+    expect(regex.test('this_is_a_very_long_name_indeed')).toBe(false);
     expect(regex.test('user name')).toBe(false);
   });
 });
diff --git a/packages/shared/src/types.ts b/packages/shared/src/types.ts
index 4a4a9dcc..3847a64e 100644
--- a/packages/shared/src/types.ts
+++ b/packages/shared/src/types.ts
@@ -1,5 +1,3 @@
-// ─── User Types ───
-
 export interface User {
   id: string;
   email: string;
@@ -24,8 +22,6 @@ export interface UpdateProfilePayload {
   accentColor?: string;
 }
 
-// ─── Platform Link Types ───
-
 export interface PlatformLink {
   id: string;
   platform: string;
@@ -44,11 +40,16 @@ export interface ReorderLinksPayload {
   links: Array<{ id: string; displayOrder: number }>;
 }
 
-// ─── Card Types ───
+export type CardVisibility = 'PUBLIC' | 'UNLISTED' | 'PRIVATE';
 
 export interface Card {
   id: string;
   title: string;
+  description?: string | null;
+  slug?: string;
+  visibility?: CardVisibility;
+  qrEnabled?: boolean;
+  viewCount?: number;
   isDefault: boolean;
   links: PlatformLink[];
 }
@@ -56,15 +57,18 @@ export interface Card {
 export interface CreateCardPayload {
   title: string;
   linkIds: string[];
+  description?: string;
+  visibility?: CardVisibility;
 }
 
 export interface UpdateCardPayload {
   title?: string;
   linkIds?: string[];
+  description?: string;
+  visibility?: CardVisibility;
+  qrEnabled?: boolean;
 }
 
-// ─── Public Profile Types ───
-
 export interface PublicProfile {
   username: string;
   displayName: string;
@@ -92,8 +96,6 @@ export interface PublicCard {
   links: PlatformLink[];
 }
 
-// ─── Follow Engine Types ───
-
 export type FollowStatus = 'idle' | 'loading' | 'success' | 'error';
 
 export interface FollowResult {
@@ -103,8 +105,6 @@ export interface FollowResult {
   message?: string;
 }
 
-// ─── Auth Types ───
-
 export interface AuthResponse {
   token: string;
   user: User;