Use Kong OAuth2 Authentication with Grape.

bridge for supporting multiple google authentication libraries

Genkan is authentication engine for Rails

Adds authentication key and stores original device registration ids on requests

Google Apps authentication

simple authentication

Authentication layer for OmniAuth

Add support of OpenStack V3 authentication

The FlexmlsApi gem handles most of the boilerplate for communicating with the flexmls API rest services, including authentication and request parsing.

A gem that provides authentication by JWT(json web token) with faye.

Allow authentication via an application token

A (really) simple gem around fb_graph for canvas authentication in Facebook

Internal authentication handlers for OmniAuth.

Rails plugin for simple Facebook session authentication

A simple rails engine to implement authentication using Facial recognition system

Email based authentication with mobile devices

Use session objects for token authentication

Devise extension to allow authentication via Stormpath

PKCS #12 authentication for Devise.

Time Based OTP/rfc6238 compatible authentication for Devise with Devise 4.2 and Rails 5 compatibility. Drop-in replacement for devise-otp.