diff --git a/src/modules/auth.ts b/src/modules/auth.ts
index fd3995f..13c35d7 100644
--- a/src/modules/auth.ts
+++ b/src/modules/auth.ts
@@ -7,6 +7,74 @@ import {
   ResetPasswordParams,
 } from "./auth.types";
 
+function isInsideIframe(): boolean {
+  if (typeof window === "undefined") return false;
+  return window !== window.parent;
+}
+
+/**
+ * Opens a URL in a centered popup and waits for the backend to postMessage
+ * the auth result back. On success, redirects the current window to
+ * redirectUrl with the token params appended, preserving the same behaviour
+ * as a normal full-page redirect flow.
+ *
+ * @param url - The login URL to open in the popup (should include popup_origin).
+ * @param redirectUrl - Where to redirect after auth (the original fromUrl).
+ * @param expectedOrigin - The origin we expect the postMessage to come from.
+ */
+function loginViaPopup(
+  url: string,
+  redirectUrl: string,
+  expectedOrigin: string
+): void {
+  const width = 500;
+  const height = 600;
+  const left = Math.round(window.screenX + (window.outerWidth - width) / 2);
+  const top = Math.round(window.screenY + (window.outerHeight - height) / 2);
+
+  const popup = window.open(
+    url,
+    "base44_auth",
+    `width=${width},height=${height},left=${left},top=${top},resizable=yes,scrollbars=yes`
+  );
+
+  if (!popup) {
+    return;
+  }
+
+  const cleanup = () => {
+    window.removeEventListener("message", onMessage);
+    clearInterval(pollTimer);
+    if (!popup.closed) popup.close();
+  };
+
+  const onMessage = (event: MessageEvent) => {
+    if (event.origin !== expectedOrigin) return;
+    if (event.source !== popup) return;
+    if (!event.data?.access_token) return;
+
+    cleanup();
+
+    const callbackUrl = new URL(redirectUrl);
+    const { access_token, is_new_user } = event.data;
+
+    callbackUrl.searchParams.set("access_token", access_token);
+
+    if (is_new_user != null) {
+      callbackUrl.searchParams.set("is_new_user", String(is_new_user));
+    }
+
+    window.location.href = callbackUrl.toString();
+  };
+
+  // Only used to detect the user closing the popup before auth completes
+  const pollTimer = setInterval(() => {
+    if (popup.closed) cleanup();
+  }, 500);
+
+  window.addEventListener("message", onMessage);
+}
+
 /**
  * Creates the auth module for the Base44 SDK.
  *
@@ -74,7 +142,14 @@ export function createAuthModule(
 
       const loginUrl = `${options.appBaseUrl}/api${authPath}?${queryParams}`;
 
-      // Redirect to the provider login page
+      // When running inside an iframe, use a popup to avoid OAuth providers
+      // blocking iframe navigation.
+      if (isInsideIframe()) {
+        const popupLoginUrl = `${loginUrl}&popup_origin=${encodeURIComponent(window.location.origin)}`;
+        return loginViaPopup(popupLoginUrl, redirectUrl, window.location.origin);
+      }
+
+      // Default: full-page redirect
       window.location.href = loginUrl;
     },
 
@@ -234,5 +309,6 @@ export function createAuthModule(
         new_password: newPassword,
       });
     },
+
   };
 }
diff --git a/tests/unit/auth.test.js b/tests/unit/auth.test.js
index 81aa9aa..c31f7a1 100644
--- a/tests/unit/auth.test.js
+++ b/tests/unit/auth.test.js
@@ -632,15 +632,244 @@ describe('Auth Module', () => {
       // Mock network error
       scope.get(`/api/apps/${appId}/entities/User/me`)
         .replyWithError('Network error');
-        
+
       // Call the API
       const result = await base44.auth.isAuthenticated();
-      
+
       // Verify the response
       expect(result).toBe(false);
-      
+
       // Verify all mocks were called
       expect(scope.isDone()).toBe(true);
     });
   });
+
+  describe('loginWithProvider()', () => {
+    test('should redirect to google login URL by default', () => {
+      const originalWindow = global.window;
+      const mockLocation = { href: '', origin: 'https://myapp.com' };
+      const win = { location: mockLocation };
+      win.parent = win; // not in iframe
+      global.window = win;
+
+      base44.auth.loginWithProvider('google', '/dashboard');
+
+      expect(mockLocation.href).toContain(`${appBaseUrl}/api/apps/auth/login?`);
+      expect(mockLocation.href).toContain(`app_id=${appId}`);
+      expect(mockLocation.href).toContain('from_url=');
+
+      global.window = originalWindow;
+    });
+
+    test('should include provider path for non-google providers', () => {
+      const originalWindow = global.window;
+      const mockLocation = { href: '', origin: 'https://myapp.com' };
+      const win = { location: mockLocation };
+      win.parent = win;
+      global.window = win;
+
+      base44.auth.loginWithProvider('microsoft', '/dashboard');
+
+      expect(mockLocation.href).toContain('/api/apps/auth/microsoft/login?');
+
+      global.window = originalWindow;
+    });
+
+    test('should use SSO URL structure for sso provider', () => {
+      const originalWindow = global.window;
+      const mockLocation = { href: '', origin: 'https://myapp.com' };
+      const win = { location: mockLocation };
+      win.parent = win;
+      global.window = win;
+
+      base44.auth.loginWithProvider('sso', '/dashboard');
+
+      expect(mockLocation.href).toContain(`/api/apps/${appId}/auth/sso/login?`);
+
+      global.window = originalWindow;
+    });
+
+    test('should use popup when inside an iframe', () => {
+      const originalWindow = global.window;
+      const mockPopup = { closed: false, close: vi.fn() };
+      const mockLocation = { href: '', origin: 'https://myapp.com' };
+      // Simulate iframe: window.parent !== window
+      const parentWindow = {};
+      global.window = {
+        location: mockLocation,
+        parent: parentWindow,
+        screenX: 0,
+        screenY: 0,
+        outerWidth: 1024,
+        outerHeight: 768,
+        open: vi.fn().mockReturnValue(mockPopup),
+        addEventListener: vi.fn(),
+        removeEventListener: vi.fn(),
+      };
+
+      base44.auth.loginWithProvider('google', '/dashboard');
+
+      // Should NOT have redirected
+      expect(mockLocation.href).toBe('');
+      // Should have opened a popup
+      expect(global.window.open).toHaveBeenCalledTimes(1);
+      const openCall = global.window.open.mock.calls[0];
+      expect(openCall[0]).toContain('popup_origin=');
+      expect(openCall[1]).toBe('base44_auth');
+
+      global.window = originalWindow;
+    });
+
+    test('should not use popup when not inside an iframe', () => {
+      const originalWindow = global.window;
+      const mockLocation = { href: '', origin: 'https://myapp.com' };
+      // window.parent === window (not in iframe)
+      const win = { location: mockLocation, open: vi.fn() };
+      win.parent = win;
+      global.window = win;
+
+      base44.auth.loginWithProvider('google', '/dashboard');
+
+      // Should have redirected directly
+      expect(mockLocation.href).toContain(`${appBaseUrl}/api/apps/auth/login?`);
+      // Should NOT have opened a popup
+      expect(global.window.open).not.toHaveBeenCalled();
+
+      global.window = originalWindow;
+    });
+
+    test('should handle popup being blocked by browser', () => {
+      const originalWindow = global.window;
+      const mockLocation = { href: '', origin: 'https://myapp.com' };
+      const parentWindow = {};
+      global.window = {
+        location: mockLocation,
+        parent: parentWindow,
+        screenX: 0,
+        screenY: 0,
+        outerWidth: 1024,
+        outerHeight: 768,
+        open: vi.fn().mockReturnValue(null), // popup blocked
+        addEventListener: vi.fn(),
+        removeEventListener: vi.fn(),
+      };
+
+      // Should not throw
+      expect(() => {
+        base44.auth.loginWithProvider('google', '/dashboard');
+      }).not.toThrow();
+
+      global.window = originalWindow;
+    });
+
+    test('should redirect on postMessage with valid token from popup', () => {
+      const originalWindow = global.window;
+      const mockPopup = { closed: false, close: vi.fn() };
+      const mockLocation = { href: '', origin: 'https://myapp.com' };
+      const parentWindow = {};
+      let messageHandler;
+      global.window = {
+        location: mockLocation,
+        parent: parentWindow,
+        screenX: 0,
+        screenY: 0,
+        outerWidth: 1024,
+        outerHeight: 768,
+        open: vi.fn().mockReturnValue(mockPopup),
+        addEventListener: vi.fn((event, handler) => {
+          if (event === 'message') messageHandler = handler;
+        }),
+        removeEventListener: vi.fn(),
+      };
+
+      base44.auth.loginWithProvider('google', '/callback');
+
+      // Simulate postMessage from popup
+      messageHandler({
+        origin: 'https://myapp.com',
+        source: mockPopup,
+        data: { access_token: 'test-token-123', is_new_user: true },
+      });
+
+      // Should redirect with token params
+      expect(mockLocation.href).toContain('access_token=test-token-123');
+      expect(mockLocation.href).toContain('is_new_user=true');
+      // Popup should be closed
+      expect(mockPopup.close).toHaveBeenCalled();
+
+      global.window = originalWindow;
+    });
+
+    test('should ignore postMessage from wrong origin', () => {
+      const originalWindow = global.window;
+      const mockPopup = { closed: false, close: vi.fn() };
+      const mockLocation = { href: '', origin: 'https://myapp.com' };
+      const parentWindow = {};
+      let messageHandler;
+      global.window = {
+        location: mockLocation,
+        parent: parentWindow,
+        screenX: 0,
+        screenY: 0,
+        outerWidth: 1024,
+        outerHeight: 768,
+        open: vi.fn().mockReturnValue(mockPopup),
+        addEventListener: vi.fn((event, handler) => {
+          if (event === 'message') messageHandler = handler;
+        }),
+        removeEventListener: vi.fn(),
+      };
+
+      base44.auth.loginWithProvider('google', '/callback');
+
+      // Simulate postMessage from wrong origin
+      messageHandler({
+        origin: 'https://evil.com',
+        source: mockPopup,
+        data: { access_token: 'stolen-token' },
+      });
+
+      // Should NOT have redirected
+      expect(mockLocation.href).toBe('');
+      expect(mockPopup.close).not.toHaveBeenCalled();
+
+      global.window = originalWindow;
+    });
+
+    test('should ignore postMessage from wrong source', () => {
+      const originalWindow = global.window;
+      const mockPopup = { closed: false, close: vi.fn() };
+      const mockLocation = { href: '', origin: 'https://myapp.com' };
+      const parentWindow = {};
+      let messageHandler;
+      global.window = {
+        location: mockLocation,
+        parent: parentWindow,
+        screenX: 0,
+        screenY: 0,
+        outerWidth: 1024,
+        outerHeight: 768,
+        open: vi.fn().mockReturnValue(mockPopup),
+        addEventListener: vi.fn((event, handler) => {
+          if (event === 'message') messageHandler = handler;
+        }),
+        removeEventListener: vi.fn(),
+      };
+
+      base44.auth.loginWithProvider('google', '/callback');
+
+      // Simulate postMessage from correct origin but different source
+      messageHandler({
+        origin: 'https://myapp.com',
+        source: {}, // not the popup
+        data: { access_token: 'stolen-token' },
+      });
+
+      // Should NOT have redirected
+      expect(mockLocation.href).toBe('');
+      expect(mockPopup.close).not.toHaveBeenCalled();
+
+      global.window = originalWindow;
+    });
+  });
 }); 
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