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After customers purchase products in your funnel, they need a way to access your app. Your app also needs to verify their identity and unlock their purchase. FunnelFox supports multiple authentication methods to hand off users from your web funnel to your mobile app. Compare each option below to choose the best fit for your implementation.

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Authentication methods

Each method balances user experience, reliability, and implementation complexity differently:
  • Email + password: Simple to integrate and reliable, but requires manual credential entry.
  • OAuth: Smooth user experience, but requires integration with your in-app authentication system.
  • Deferred deep link (DDL): Most seamless experience, but less reliable and requires a backup method.
  • Email + magic link: Most reliable with excellent user experience, but requires more implementation work.

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Email + password

The simplest and most reliable authentication method. How it works:
  1. Integrate Firebase email/password authentication with FunnelFox.
  2. Add email and password inputs to the same funnel screen. FunnelFox creates Firebase users with the credentials they provide.
If no password input is provided, the Firebase user is created with a random password that the user cannot access. You’ll need to implement a password reset flow for the in-app authentication step.
  1. Add email/password login functionality to your app.
  2. Display a login link on your in-app paywall for users who previously purchased through the funnel.
If you want to reduce friction and avoid manual password entry, consider one of the methods below. Learn how to set up Firebase email + password authentication in FunnelFox.

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OAuth

This option reduces friction by eliminating manual password entry. How it works:
  1. Integrate Firebase OAuth with FunnelFox.
  2. Add OAuth provider buttons (like Google or Apple) to your funnel screen. FunnelFox creates a Firebase user linked to the provider credentials and adds the user’s email to their customer profile.
If a user enables Hide My Email with Apple, FunnelFox stores their anonymous email address with the @privaterelay.appleid.com domain.
  1. Integrate OAuth in-app login functionality.
Learn how to set up Firebase OAuth in FunnelFox. DDLs don’t require any manual input from customers. Users move seamlessly through the funnel > install > open app > arrive identified flow in one tap. However, DDLs can fail, users may miss your Download button, and testing is challenging. Always implement a fallback authentication method to reduce support requests. How it works:
  1. Configure DDLs in AppsFlyer or Adjust with a variable containing a unique user_id or session_id as a query parameter.
  2. Add a Button element with a DDL to your last funnel screen. This is typically a Download app CTA.
  3. Process the DDL in your app and extract the user_id or session_id to sign in the user.
Learn how to set up deferred deep linking FunnelFox. Magic links eliminate password-related friction and are highly reliable. Users enter their email, receive a link, and tap it to log in. This works perfectly as a fallback when DDLs fail. To use magic links with Firebase, enable Email/Password and Email link (passwordless sign-in), then implement email link sign-in handling in your app. Depending on your setup, you may also need to set up email delivery. You can implement magic links in three ways:
Combine this method with DDLs for a complete authentication flow.
Learn how to set up Firebase in FunnelFox and how to configure magic links in Firebase.

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Next steps