Supabase Anonymous Guest Login for iOS Apps

Supabase anonymous login solves a real conversion problem: it lets someone use your app immediately, as a guest with a real session, and sign up only once they care. Done right, the upgrade later feels like saving progress, not starting over. VP0 is the free, AI-readable iOS design library builders start from for the guest and account screens, so the trial and the upgrade both feel native.

Who this is for

You are building an iOS app on Supabase, maybe with Cursor or Claude Code, and you want people to try it before hitting a signup wall. This is the guest-to-account pattern.

Why a guest path beats a signup wall

A signup form before any value is the fastest way to lose a new user. Anonymous login lets people reach the core experience first, then create an account once they are invested. About 62% of developers already use AI tools to ship features like this quickly, but the product win is the same with or without AI: fewer barriers between a new user and a first success.

Start the guest, keep security on

Call Supabase anonymous sign-in to create a real but temporary user, so the app works with no form. Critically, keep row-level security on. An anonymous user has a real user id, so your Supabase Auth policies should scope their rows to them exactly like a full account. Build the guest and upgrade screens in SwiftUI, and never treat guest as public, the same row-level discipline behind a Supabase auth screen template.

Plan the conversion

The whole point is to convert guests into permanent accounts without losing their work. Link an identity to the existing user rather than creating a new one.

State	Can do	Note
Anonymous guest	Use the app, own their rows	Real session, temporary
Upgrade prompt	Add email or social login	Feels like saving progress
Permanent account	Same data, recoverable	Same user id, linked identity

When the guest adds an email or signs in with a provider, attach it to the same user id so every row carries over, and confirm the link before treating the account as permanent. The same care over auth state shows up in a Firebase auth login screen.

A worked example: guest to member

Follow a new user. They open the app and tap Continue as guest, which calls Supabase anonymous sign-in and drops them straight into the core experience with a real session and no form to fill. They create a few items, all scoped to their anonymous user id by row-level security, so only they can see them, exactly as a full account would be.

A day later, having found the app useful, they tap Save your account and add an email or sign in with a provider. You link that identity to the existing user id rather than creating a new one, so every item they already made carries over untouched, and the prompt frames the moment as saving progress rather than signing up. They are now a permanent member with nothing lost and nothing re-entered. The guest path removed the upfront wall that loses so many new users, and the conversion landed at the moment they actually cared. The only discipline required was keeping row-level security on the whole time and linking rather than recreating the account, so a trial never becomes a security hole or a data-loss bug. Done this way, anonymous auth is not a shortcut that cuts corners, it is a deliberate funnel that meets people where they are and rewards them for staying with a frictionless upgrade.

Common mistakes and fixes

• Treating guest as public. Keep row-level security on for anonymous users.
• Creating a new user on upgrade. Link the identity to the existing id.
• A signup wall up front. Let people reach value before asking for an account.
• Losing guest data. Carry rows over by keeping the same user id.
• No upgrade nudge. Prompt to save progress once the user is invested.

Links that bring a guest back to the right screen are a deep linking and unhandled URL problem worth handling well.

Key takeaways

• Anonymous login lets users try the app before signing up, lifting conversion.
• Keep row-level security on; an anonymous user has a real id.
• Convert by linking an identity to the same user so data carries over.
• Make the upgrade feel like saving progress, from a free VP0 design.

Frequently asked questions

The FAQ above answers adding anonymous login, why it beats a signup wall, whether row-level security still works, and how to convert a guest without losing data.