Sign in / Sign up
Email sign-up collects email, username, and password. Usernames are checked for availability and length. The server emails a six-digit code (SES), you enter it in a modal, and the backend creates the Supabase user and profile.
Google uses Supabase OAuth. The callback checks origin, exchanges the code, ensures profile rows exist for new OAuth users, then sends you to the feed. You can of course sign in with OAuth on an account that was created with email.