diff --git a/web/app/account/oauth/authorize/page.spec.tsx b/web/app/account/oauth/authorize/page.spec.tsx
new file mode 100644
index 0000000000..3b367710eb
--- /dev/null
+++ b/web/app/account/oauth/authorize/page.spec.tsx
@@ -0,0 +1,127 @@
+import { fireEvent, render, screen } from '@testing-library/react'
+import { useRouter, useSearchParams } from 'next/navigation'
+import { useLanguage } from '@/app/components/header/account-setting/model-provider-page/hooks'
+import { useAppContext } from '@/context/app-context'
+import { useIsLogin } from '@/service/use-common'
+import { useAuthorizeOAuthApp, useOAuthAppInfo } from '@/service/use-oauth'
+import { storage } from '@/utils/storage'
+import { OAUTH_AUTHORIZE_PENDING_KEY, OAUTH_AUTHORIZE_PENDING_TTL, REDIRECT_URL_KEY } from './constants'
+import OAuthAuthorize from './page'
+
+vi.mock('next/navigation', () => ({
+  useRouter: vi.fn(),
+  useSearchParams: vi.fn(),
+}))
+
+vi.mock('@/app/components/header/account-setting/model-provider-page/hooks', () => ({
+  useLanguage: vi.fn(),
+}))
+
+vi.mock('@/context/app-context', () => ({
+  useAppContext: vi.fn(),
+}))
+
+vi.mock('@/service/use-common', () => ({
+  useIsLogin: vi.fn(),
+}))
+
+vi.mock('@/service/use-oauth', () => ({
+  useAuthorizeOAuthApp: vi.fn(),
+  useOAuthAppInfo: vi.fn(),
+}))
+
+const FIXED_DATE = new Date('2026-02-10T12:00:00.000Z')
+const SEARCH_QUERY = 'client_id=dcfcd6a4-5799-405a-a6d7-04261b24dd02&redirect_uri=https%3A%2F%2Fcreators.dify.dev%2Fapi%2Fv1%2Foauth%2Fcallback%2Fdify&response_type=code'
+
+const createOAuthAppInfo = () => ({
+  app_label: {
+    en_US: 'Test OAuth App',
+  },
+  scope: 'read:name',
+  app_icon: '',
+})
+
+describe('OAuthAuthorize redirect persistence', () => {
+  const push = vi.fn()
+
+  beforeEach(() => {
+    vi.clearAllMocks()
+    storage.resetCache()
+    localStorage.clear()
+    vi.useFakeTimers()
+    vi.setSystemTime(FIXED_DATE)
+
+    vi.mocked(useRouter).mockReturnValue({
+      push,
+    } as never)
+    vi.mocked(useSearchParams).mockReturnValue(new URLSearchParams(SEARCH_QUERY) as never)
+    vi.mocked(useLanguage).mockReturnValue('en_US')
+    vi.mocked(useAppContext).mockReturnValue({
+      userProfile: {
+        avatar_url: '',
+        name: 'Dify User',
+        email: 'dify@example.com',
+      },
+    } as never)
+    vi.mocked(useOAuthAppInfo).mockReturnValue({
+      data: createOAuthAppInfo(),
+      isLoading: false,
+      isError: false,
+    } as never)
+    vi.mocked(useAuthorizeOAuthApp).mockReturnValue({
+      mutateAsync: vi.fn(),
+      isPending: false,
+    } as never)
+  })
+
+  afterEach(() => {
+    vi.useRealTimers()
+  })
+
+  it('should store full authorize url and navigate to signin when switch account is clicked', () => {
+    // Arrange
+    vi.mocked(useIsLogin).mockReturnValue({
+      isLoading: false,
+      data: { logged_in: true },
+    } as never)
+    render(<OAuthAuthorize />)
+    const switchAccountButton = screen.getByRole('button', { name: 'oauth.switchAccount' })
+
+    // Act
+    fireEvent.click(switchAccountButton)
+
+    // Assert
+    const expectedStoredReturnUrl = `${window.location.origin}/account/oauth/authorize?${SEARCH_QUERY}`
+    const expectedDecodedReturnUrl = decodeURIComponent(expectedStoredReturnUrl)
+    expect(push).toHaveBeenCalledTimes(1)
+    const pushedUrl = push.mock.calls[0][0] as string
+    const pushedParams = new URLSearchParams(pushedUrl.split('?')[1])
+    expect(pushedParams.has(REDIRECT_URL_KEY)).toBe(true)
+    expect(decodeURIComponent(pushedParams.get(REDIRECT_URL_KEY)!)).toBe(expectedDecodedReturnUrl)
+
+    const storedPendingRedirect = storage.get<{ value: string, expiry: number }>(OAUTH_AUTHORIZE_PENDING_KEY)
+    expect(storedPendingRedirect).toEqual({
+      value: expectedStoredReturnUrl,
+      expiry: Math.floor((FIXED_DATE.getTime() + OAUTH_AUTHORIZE_PENDING_TTL * 1000) / 1000),
+    })
+  })
+
+  it('should store full authorize url and navigate to signin when login button is clicked for logged-out users', () => {
+    // Arrange
+    vi.mocked(useIsLogin).mockReturnValue({
+      isLoading: false,
+      data: { logged_in: false },
+    } as never)
+    render(<OAuthAuthorize />)
+    const loginButton = screen.getByRole('button', { name: 'oauth.login' })
+
+    // Act
+    fireEvent.click(loginButton)
+
+    // Assert
+    const expectedReturnUrl = `${window.location.origin}/account/oauth/authorize?${SEARCH_QUERY}`
+    expect(push).toHaveBeenCalledTimes(1)
+    expect(push).toHaveBeenCalledWith(`/signin?${REDIRECT_URL_KEY}=${encodeURIComponent(expectedReturnUrl)}`)
+    expect(storage.get<{ value: string }>(OAUTH_AUTHORIZE_PENDING_KEY)?.value).toBe(expectedReturnUrl)
+  })
+})
diff --git a/web/app/account/oauth/authorize/page.tsx b/web/app/account/oauth/authorize/page.tsx
index ea375e1a32..bc7cd1668e 100644
--- a/web/app/account/oauth/authorize/page.tsx
+++ b/web/app/account/oauth/authorize/page.tsx
@@ -85,7 +85,8 @@ export default function OAuthAuthorize() {
   const isLoading = isOAuthLoading || isIsLoginLoading
   const onLoginSwitchClick = () => {
     try {
-      const returnUrl = buildReturnUrl('/account/oauth/authorize', `?client_id=${encodeURIComponent(client_id)}&redirect_uri=${encodeURIComponent(redirect_uri)}`)
+      const authorizeQuery = searchParams.toString()
+      const returnUrl = buildReturnUrl('/account/oauth/authorize', authorizeQuery ? `?${authorizeQuery}` : '')
       setItemWithExpiry(OAUTH_AUTHORIZE_PENDING_KEY, returnUrl, OAUTH_AUTHORIZE_PENDING_TTL)
       router.push(`/signin?${REDIRECT_URL_KEY}=${encodeURIComponent(returnUrl)}`)
     }
diff --git a/web/app/page.spec.tsx b/web/app/page.spec.tsx
new file mode 100644
index 0000000000..c97610d6b9
--- /dev/null
+++ b/web/app/page.spec.tsx
@@ -0,0 +1,71 @@
+import { redirect } from 'next/navigation'
+import Home from './page'
+
+vi.mock('next/navigation', () => ({
+  redirect: vi.fn(),
+}))
+
+describe('Home page redirect', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  it('should redirect to /apps when search params are empty', async () => {
+    // Arrange
+    const props = {
+      searchParams: Promise.resolve({}),
+    }
+
+    // Act
+    await Home(props)
+
+    // Assert
+    expect(redirect).toHaveBeenCalledWith('/apps')
+  })
+
+  it('should preserve single query param when redirecting to /apps', async () => {
+    // Arrange
+    const props = {
+      searchParams: Promise.resolve({
+        oauth_redirect_url: 'https://example.com/callback',
+      }),
+    }
+
+    // Act
+    await Home(props)
+
+    // Assert
+    expect(redirect).toHaveBeenCalledWith('/apps?oauth_redirect_url=https%3A%2F%2Fexample.com%2Fcallback')
+  })
+
+  it('should preserve repeated query params when redirecting to /apps', async () => {
+    // Arrange
+    const props = {
+      searchParams: Promise.resolve({
+        scope: ['read:name', 'read:email'],
+      }),
+    }
+
+    // Act
+    await Home(props)
+
+    // Assert
+    expect(redirect).toHaveBeenCalledWith('/apps?scope=read%3Aname&scope=read%3Aemail')
+  })
+
+  it('should ignore undefined query values when building redirect url', async () => {
+    // Arrange
+    const props = {
+      searchParams: Promise.resolve({
+        client_id: 'abc',
+        state: undefined,
+      }),
+    }
+
+    // Act
+    await Home(props)
+
+    // Assert
+    expect(redirect).toHaveBeenCalledWith('/apps?client_id=abc')
+  })
+})
diff --git a/web/app/signin/utils/post-login-redirect.spec.ts b/web/app/signin/utils/post-login-redirect.spec.ts
new file mode 100644
index 0000000000..f6839319d4
--- /dev/null
+++ b/web/app/signin/utils/post-login-redirect.spec.ts
@@ -0,0 +1,149 @@
+import type { ReadonlyURLSearchParams } from 'next/navigation'
+import { OAUTH_AUTHORIZE_PENDING_KEY, REDIRECT_URL_KEY } from '@/app/account/oauth/authorize/constants'
+import { storage } from '@/utils/storage'
+import { resolvePostLoginRedirect } from './post-login-redirect'
+
+const FIXED_DATE = new Date('2026-02-10T12:00:00.000Z')
+
+const createSearchParams = (params: Record<string, string>) => {
+  return new URLSearchParams(params) as unknown as ReadonlyURLSearchParams
+}
+
+const setPendingRedirect = (value: unknown) => {
+  storage.set(OAUTH_AUTHORIZE_PENDING_KEY, value as never)
+}
+
+describe('resolvePostLoginRedirect', () => {
+  let consoleErrorSpy: ReturnType<typeof vi.spyOn>
+
+  beforeEach(() => {
+    vi.clearAllMocks()
+    storage.resetCache()
+    localStorage.clear()
+    vi.useFakeTimers()
+    vi.setSystemTime(FIXED_DATE)
+    consoleErrorSpy = vi.spyOn(console, 'error').mockImplementation(() => {})
+  })
+
+  afterEach(() => {
+    vi.useRealTimers()
+    consoleErrorSpy.mockRestore()
+  })
+
+  describe('redirect_url priority', () => {
+    it('should return decoded redirect_url when query param exists', () => {
+      // Arrange
+      setPendingRedirect({
+        value: '/stale-pending',
+        expiry: Math.floor(Date.now() / 1000) + 60,
+      })
+      const redirectUrl = 'https://example.com/account/oauth/authorize?client_id=abc'
+      const searchParams = createSearchParams({
+        [REDIRECT_URL_KEY]: encodeURIComponent(redirectUrl),
+      })
+
+      // Act
+      const result = resolvePostLoginRedirect(searchParams)
+
+      // Assert
+      expect(result).toBe(redirectUrl)
+      expect(storage.get(OAUTH_AUTHORIZE_PENDING_KEY)).toBeNull()
+    })
+
+    it('should return original redirect_url when decoding fails', () => {
+      // Arrange
+      setPendingRedirect({
+        value: '/stale-pending',
+        expiry: Math.floor(Date.now() / 1000) + 60,
+      })
+      const malformedRedirectUrl = '%E0%A4%A'
+      const searchParams = createSearchParams({
+        [REDIRECT_URL_KEY]: malformedRedirectUrl,
+      })
+
+      // Act
+      const result = resolvePostLoginRedirect(searchParams)
+
+      // Assert
+      expect(result).toBe(malformedRedirectUrl)
+      expect(storage.get(OAUTH_AUTHORIZE_PENDING_KEY)).toBeNull()
+      expect(consoleErrorSpy).toHaveBeenCalledTimes(1)
+    })
+  })
+
+  describe('pending redirect fallback', () => {
+    it('should return pending redirect when redirect_url is absent and pending is valid', () => {
+      // Arrange
+      const pendingRedirect = 'https://skills.bash-is-all-you-need.dify.dev/account/oauth/authorize?client_id=dcfcd6a4-5799-405a-a6d7-04261b24dd02&redirect_uri=https%3A%2F%2Fcreators.dify.dev%2Fapi%2Fv1%2Foauth%2Fcallback%2Fdify&response_type=code'
+      setPendingRedirect({
+        value: pendingRedirect,
+        expiry: Math.floor(Date.now() / 1000) + 60,
+      })
+
+      // Act
+      const result = resolvePostLoginRedirect(createSearchParams({}))
+
+      // Assert
+      expect(result).toBe(pendingRedirect)
+      expect(storage.get(OAUTH_AUTHORIZE_PENDING_KEY)).toBeNull()
+    })
+
+    it('should consume pending redirect only once', () => {
+      // Arrange
+      const pendingRedirect = '/account/oauth/authorize?client_id=one-time'
+      setPendingRedirect({
+        value: pendingRedirect,
+        expiry: Math.floor(Date.now() / 1000) + 60,
+      })
+
+      // Act
+      const firstResult = resolvePostLoginRedirect(createSearchParams({}))
+      const secondResult = resolvePostLoginRedirect(createSearchParams({}))
+
+      // Assert
+      expect(firstResult).toBe(pendingRedirect)
+      expect(secondResult).toBeNull()
+    })
+
+    it('should return null when pending redirect is expired', () => {
+      // Arrange
+      setPendingRedirect({
+        value: '/account/oauth/authorize?client_id=expired',
+        expiry: Math.floor(Date.now() / 1000) - 1,
+      })
+
+      // Act
+      const result = resolvePostLoginRedirect(createSearchParams({}))
+
+      // Assert
+      expect(result).toBeNull()
+      expect(storage.get(OAUTH_AUTHORIZE_PENDING_KEY)).toBeNull()
+    })
+
+    it('should return null when pending redirect payload is invalid', () => {
+      // Arrange
+      setPendingRedirect({
+        value: '/account/oauth/authorize?client_id=invalid',
+      })
+
+      // Act
+      const result = resolvePostLoginRedirect(createSearchParams({}))
+
+      // Assert
+      expect(result).toBeNull()
+    })
+  })
+
+  describe('empty state', () => {
+    it('should return null when no redirect_url and no pending redirect exist', () => {
+      // Arrange
+      const searchParams = createSearchParams({})
+
+      // Act
+      const result = resolvePostLoginRedirect(searchParams)
+
+      // Assert
+      expect(result).toBeNull()
+    })
+  })
+})
diff --git a/web/app/signin/utils/post-login-redirect.ts b/web/app/signin/utils/post-login-redirect.ts
index c106a629a7..8dd36d2524 100644
--- a/web/app/signin/utils/post-login-redirect.ts
+++ b/web/app/signin/utils/post-login-redirect.ts
@@ -8,28 +8,12 @@ type OAuthPendingRedirect = {
   expiry?: number
 }
 
-function getLegacyOAuthPendingRedirect(): OAuthPendingRedirect | null {
-  try {
-    const itemStr = localStorage.getItem(OAUTH_AUTHORIZE_PENDING_KEY)
-    return itemStr ? JSON.parse(itemStr) : null
-  }
-  catch {
-    return null
-  }
-}
-
 function removeOAuthPendingRedirect() {
   storage.remove(OAUTH_AUTHORIZE_PENDING_KEY)
-  try {
-    localStorage.removeItem(OAUTH_AUTHORIZE_PENDING_KEY)
-  }
-  catch {
-    // ignore legacy key cleanup failures
-  }
 }
 
 function getOAuthPendingRedirect(): string | null {
-  const item = storage.get<OAuthPendingRedirect>(OAUTH_AUTHORIZE_PENDING_KEY) ?? getLegacyOAuthPendingRedirect()
+  const item = storage.get<OAuthPendingRedirect>(OAUTH_AUTHORIZE_PENDING_KEY)
   if (!item)
     return null