How do I fix "Confirmation email link goes to localhost:3000"?

Set the Site URL in your auth settings to your live address. Add your live address (and preview addresses) to the allowed redirect URLs. Build redirect addresses from a production setting, not a hard-coded localhost.

Confirmation email link goes to localhost:3000

Supabase Auth
Any auth provider

What it means

Your auth provider builds email links from a site address you set during development. It still says localhost, so real users get links to their own computer.

Why it happens

The Site URL in your auth settings is still http://localhost:3000.
The app passes a redirect address built from a development setting.

How to fix it

Set the Site URL in your auth settings to your live address.
Add your live address (and preview addresses) to the allowed redirect URLs.
Build redirect addresses from a production setting, not a hard-coded localhost.

Let your AI find the cause

Paste this into Claude Code, Cursor, Lovable or whichever AI built your app. It looks first and changes nothing until you have read the answer.

My app's confirmation and reset emails link to localhost. Without changing anything yet, show me where this project sets the redirect address for auth emails and which setting in my auth provider controls the Site URL.