Do I need account linking if users can sign in with Google and email?

Not necessarily.

If users can sign in with both Google and email/password (or magic link), you only need account linking if you want both sign-in methods to map to the same user account.

You do not need account linking if:

• A Google login creates one account, and
• Email login creates a separate account,
• and you’re okay with those being different users unless manually merged.

You do need account linking if:

• You want a user who signs in with Google and later with email to always see the same profile/data.
• You want to prevent duplicate accounts for the same person.
• You want to support “continue with Google” and “sign in with email” for the same identity.

Typical behavior

If someone signs up with:

• Google first, then tries email later, or
• Email first, then Google later,

the auth system will often treat those as two separate identities unless you explicitly link them.

Common approaches

1. No linking

   • Simplest.
   • Separate accounts per provider.

2. Automatic linking

   • Link providers when you’re confident they belong to the same person (usually tricky and can be risky).

3. User-driven linking

   • Let the user sign in with one method, then in settings connect another method.

Rule of thumb

• If your app stores user-specific data and you want one unified profile: yes, you probably need linking.
• If you’re fine with separate accounts per login method: no, you don’t need it.

If you want, I can also explain how this works specifically in Auth.js / NextAuth, Firebase, or Supabase.