Sign-in for your app

Your app's users can sign in with an email and password, or with Google, GitHub or LinkedIn. You don't need to create a developer account, register an app or copy any keys.

Just ask

Describe what you want in the chat:

• "Add a login page with email and password."
• "Let people sign in with Google."
• "Add GitHub and LinkedIn login next to the email form."

The builder writes the sign-in pages, the user accounts in your project's database and the protected routes. When the change is applied, it also turns the matching switches on in Project settings → Authentication and gives your app everything it needs. The preview restarts with sign-in working.

Apps whose features need accounts — an admin panel, a dashboard, personal records — get email and password sign-in even if you didn't ask for it. The switch turns on by itself.

How Google, GitHub and LinkedIn work without keys

Normally each of these needs an app registered in the provider's developer console, with a client ID, a secret and exact redirect addresses. SpinBuild runs that part for you:

1. A visitor clicks Continue with Google in your app.
2. They sign in on Google's own page, which shows they are signing in through SpinBuild.
3. Google sends them back, and your app receives their name, email address and picture. It then signs them in with its own account system, the same way as a password login.

The visitor is only ever sent back to your project's own addresses: the preview, the published app and its custom domains. Your app's server confirms each sign-in with a secret that SpinBuild keeps in its environment and never shows in the browser.

Using your own provider app

If you would rather have your app's name on Google's screen, open Project settings → Authentication, expand the provider, choose Use my own Google app, and paste your client ID and secret. The page lists the exact redirect addresses to register. You can switch back to SpinBuild's sign-in at any time.

Turning a method off

Turn its switch off in Project settings → Authentication. The app's environment is updated straight away. Ask the builder to remove the button if you no longer want it on the page.

From an AI tool connected over MCP

Connected tools can do the same: get_my_project_auth returns the integration details to code against, and set_my_project_auth turns a method on or off. Saving code that adds password login with save_my_project switches email and password on by itself. See MCP.