Flutter Anonymous Sign-In Template - Firebase, Supabase, REST API

Fast to integrate

One CLI command generates your project with the options you need

Customizable

Composable widgets that inherit your Flutter ThemeData.

Flexible

Works with any backend or Firebase and Supabase, one command configures everything.

Flutter anonymous sign-in template — try the app before creating an account

AUTH MODE

Frictionless start, no signup

Most users abandon when they hit a signup form. Anonymous sign-in skips it entirely: a real authenticated session is created on first launch, so users can store data, save preferences and even pay before they ever create an account. When they decide to sign up, the existing user ID is linked to the new account and nothing is lost. Choose your backend — Firebase, Supabase, or your own REST API — and the CLI configures everything.

Firebase Auth

Built-in anonymous sign-in with token rotation and refresh

Supabase Auth

Anonymous users supported since Supabase 4.x — same flow as Firebase

Flutter anonymous account linking — Google and Apple upgrade flow

UPGRADE PATH

Keep user data when they sign up

When an anonymous user decides to create a real account, you do not want to start from scratch. The template links the new identity to the existing anonymous user ID, so purchases, preferences and any data already in your database stay attached. Works with Google, Apple, email/password and phone — see the Supabase tip and Firebase auth doc for the full pattern.

Email linking

Link the anonymous user to an email account

Social linking

Link the anonymous user to a social account in one call

onLinkedAccount hook

Triggered after upgrade — push the email to your CRM or marketing list

ID preserved

Anonymous user ID survives the upgrade so data stays attached

CODE

Clean architecture, fully tested

The anonymous auth module follows the three-layer architecture pattern with Riverpod state management. The authentication state is reactive — your entire app responds to anonymous sign-in and upgrade events automatically. Includes unit tests for the anonymous flow and the linking flow so you can refactor with confidence.

Riverpod state

Reactive auth state across the entire app — anonymous, authenticated, loading

Unit tested

Anonymous sign-in and account-linking flows covered with tests

Reactive upgrades

UI auto-updates the moment an anonymous user upgrades to a real account

Works with the full authentication flow

Anonymous sign-in is the entry point. Combine it with the email login, signup template, social logins (Google, Apple, Facebook), phone authentication, and forgot password — every upgrade path is covered.

Pair it with onboarding and paywall to let users explore your app, hit value, then upgrade — all without ever showing a signup form too early.