What is OAuth?

OAuth 2.0 is the protocol behind every "Sign in with Google," "Sign in with Apple," and "Continue with Facebook" button you have ever used. It lets users authenticate with a trusted provider and grant your app limited access to their profile information — without ever sharing their password with you.

How OAuth Works

The OAuth flow involves four parties: the user, your application, the authorization server (e.g., Google), and the resource server (e.g., Google's user profile API).

When a user taps "Sign in with Google," your app redirects them to Google's authorization page. The user logs in with Google and approves the permissions your app requests. Google redirects back to your app with an authorization code. Your app exchanges that code for an access token. Your app uses the access token to fetch the user's profile from Google's API.

At no point does your application see or store the user's Google password.

Why OAuth Matters

Security. Users do not need to create yet another password for your app. Fewer passwords mean fewer opportunities for credential theft.

User experience. Social login reduces sign-up friction. According to research by LoginRadius, social login can increase conversion rates by 20-40% compared to traditional email/password forms.

Trust. Users trust established providers like Google and Apple with their credentials more than they trust a new app.

OAuth vs Authentication vs Authorization

Authentication answers "who are you?" — verifying identity. Authorization answers "what can you do?" — granting permissions. OAuth is primarily an authorization protocol, though it is commonly used alongside OpenID Connect (OIDC) to handle authentication as well.

OAuth at App369

At App369, we implement OAuth-based social login in the majority of our mobile and web apps using Firebase Authentication, which supports Google, Apple, Facebook, Twitter, and custom providers out of the box. Contact us to discuss authentication for your app.