Firebase · sdk · fg-0188

Firebase email link sign-in links stop opening the iOS or Android app after the Dynamic Links shutdown

Email sign-in, password reset, or verify links open a browser page instead of the app

Verified 2026-10-15 · Confirmed by 0 builders · Trust 50/100

Cause

Mobile email link handling relied on Firebase Dynamic Links, which shut down on August 25, 2025. Auth now uses the project's Firebase Hosting domain, which the app must be configured to open.

Fix

Update the Auth SDKs, set up App Links or Universal Links for PROJECT_ID.firebaseapp.com or a custom Hosting domain, and pass that domain as linkDomain in ActionCodeSettings.

Apply

const actionCodeSettings = {
  url: 'https://example.com/finishSignUp',
  handleCodeInApp: true,
  linkDomain: 'auth.example.com', // Firebase Hosting domain
  iOS: { bundleId: 'com.example.ios' },
  android: { packageName: 'com.example.android', installApp: true },
};
await sendSignInLinkToEmail(auth, email, actionCodeSettings);

Affects: Firebase Auth email link, password reset, and verification flows handled in mobile apps after 2025-08-25; Android needs Auth SDK 23.2.0+ (BoM 33.9.0+)

Sources

• https://firebase.google.com/support/dynamic-links-faq
• https://firebase.google.com/docs/auth/android/email-link-migration

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