Google Sign-In is a secure authentication system that reduces the burden of login for your users, by enabling them to sign in with their Google account—the same account they already use with Gmail, Play, Google+, and other Google services.
Google Sign-In is also your gateway to connecting with Google’s users and services in a secure manner. You can give your users the opportunity to pay with Android Pay, share with their Google-wide contacts, save a file to Drive, add an event to Calendar, and more. Integrate Google’s user-centric APIs and services inside your app to help your users take action and convert.
See some case studies of successful Google Sign-In integrations.
With Smart Lock for Passwords, you get frictionless sign-in and sign-up into apps on Android and sites in Chrome with any account. Users will get automatically signed-in across devices.
In turn, you reduce the risk of forgotten user passwords and missed conversion opportunities when users get frustrated trying to sign in or move on to another activity.
Once your user saves a password to Smart Lock, they can skip entering their credentials on all of their Chrome and Android devices.AndroidChrome
See some case studies of successful Smart Lock for Passwords integrations.
Firebase Authentication makes building secure authentication easy, providing sign-in and on-boarding for your users on all their devices.
It provides backend services to securely authenticate users, paired with easy-to-use client SDKs. It can authenticate users using passwords and federated identity provider credentials.
Firebase Authentication also provides UI libraries to implement a full authentication experience in your app.
Securely call Google APIs with OAuth 2.0 authorization.
Build your own sign-in solution with Google's OpenID Connect endpoint.