Email link authentication previously relied onFirebase Dynamic Links, which will beshut down on August 25, 2025. We've published analternative solution in theFirebase Authentication Android SDK version 23.2.0+ andFirebase BoM version 33.9.0+. If your app uses the old style links and youwant to use an alternative method for migrating your app, seeAuthenticate with Firebase using Email Link in Androidto use the newFirebase Hosting based system.

Also, if you're using theFirebase Authentication Android SDK below v20.0.0 (or theFirebase BoM below v26.0.0) to manage OAuth flows withFirebase Authentication,you'll need to update to the latestAuthentication SDK orBoM version(Authentication v20.0.0+ orBoM v26.0.0+) in order to continue managing OAuthflows inFirebase Authentication.

Migrate your associatedFirebase Dynamic Links domain to aFirebase Hosting domain

Moving forward, rather than using aFirebase Dynamic Links domain,Firebase Authenticationwill use theFirebase Hosting default domain for your project to createlinks for email link and other out-of-band link actions in mobile apps. Thismeans that your app will also need to be updated to use this default domain asthe associated domain for email authentication links to your mobile app.

You can follow the instructions inAuthenticate with Firebase Using Email Link in Android to update your mobile app linksto use the new automatically provisionedFirebase Hosting default domain.

Use the following instructions to handle links from the new domain and toinstructFirebase Authentication to start using the new domain to generate mobile applinks going forward.

If you'd like to continue using any of your customFirebase Hosting domainsor even your customFirebase Dynamic Links domain to be your new associateddomain, follow the steps that match the intended domain you'd like to use. Notethat after completing the instructions in the following section, the deeplinking feature on yourFirebase Dynamic Links custom domain will be removed;only the domain itself will remain for creating email links.

1. Configure your Android application to handle yourFirebase Hosting link

   1. In order to handle these links from your Android application, your app'spackage name needs to be specified in theFirebase consoleproject settings. In addition, the SHA-1 and SHA-256 of the applicationcertificate need to be provided.

   2. If you want theseFirebase Hosting links to redirect to a specificactivity, you will need to configure an intent filter in yourAndroidManifest.xml file. The intent filter should catchFirebase Hosting links of your domain. InAndroidManifest.xml:

      <intent-filterandroid:autoVerify="true"><actionandroid:name="android.intent.action.VIEW"/><categoryandroid:name="android.intent.category.BROWSABLE"/><categoryandroid:name="android.intent.category.DEFAULT"/><dataandroid:scheme="https"android:host="PROJECT_ID.firebaseapp.comoracustomhostingdomain"android:pathPrefix="/__/auth/links"/></intent-filter>

   When users open a hosting link with the "/__/auth/links" path and thescheme and host you specify, your app will start the activity with thisintent filter to handle the link.

   Important: To ensure a seamless rollback, we recommend keeping yourexisting intent filter that handlesFirebase Dynamic Links while trying out theFirebase Hosting link solution. TheFirebase Dynamic Links solution will beavailable until August 25, 2025.

2. Configure your project to use the new links

   When you're ready to handle the new domain links, you can use theFirebase Admin SDK to update how you want email linksto be generated and instruct our backend to start generating links usingthe newFirebase Hosting domain.

   import{getAuth}from'firebase-admin/auth';constupdateEmailAuthDomain=async()=>{constupdateRequest={mobileLinksConfig:{domain:'HOSTING_DOMAIN',},};constprojectConfigManager=getAuth().projectConfigManager();try{constresponse=awaitprojectConfigManager.updateProjectConfig(updateRequest);// Updated project configconsole.log('Project configuration updated successfully:',response);}catch(error){console.error('Error updating the project:',error);}};

   Important: To rollback to theFirebase Dynamic Links while implementing andtesting the backup solution, you should set the domain back toFIREBASE_DYNAMIC_LINK. TheFirebase Dynamic Links solution will beavailable until August 25, 2025.

3. Send and redeem the email link

   Send the email sign-in link as before. When the end user clicks the link,they will be redirected to the app if installed to complete the sign-in.

Customize your mobile links

You can use a customFirebase Hosting domain or reuse your customFirebase Dynamic Links domain to be your new mobile links domain.

Use a customFirebase Hosting domain

1. Follow theFirebase Hosting guide to set up acustom domain.
2. Configure your Android application to handle yourFirebase Hosting link.(instructions in previous section above).
3. Send an authentication link to the user's emailaddresswith an updatedActionCodeSettings object with a custom domain aslinkDomain.

Re-use your customFirebase Dynamic Links domain

1. You can re-use any of yourFirebase Dynamic Links domains as your customdomain. However, anyFirebase Dynamic Links functionality will no longer besupported (for example, users cannot be redirected to an app store if theapp isn't installed on their device).
2. Configure your Android application to handle yourFirebase Hosting link(instructions in previous section above).
3. Send an authentication link to the user's emailaddresswith an updatedActionCodeSettings object with a custom domain aslinkDomain.