Ruby on Rails 7 Authentication and User Management Engine using Devise with a nice-looking dashboard, admin panel and login views to get you going fast on your next project.

JWT Token Authenticationt

jwt-bouncer is an abstraction for JWT-based authentication/authorisation

Json Web Token Authentication for devise users. It can be use for APIs.

Authentication middleware for Rails API that uses JWTs

Roles Management interface for virtually every backend, mostly like OmniAuth for authentication

Bare essentials to quickly implement a custom authentication system on Rails using Warden.

Koinz clients require authentication via oauth koinz provider. They can also publish/subscribe for notifications in the koinz environment.

OAuth2 (Facebook Connect) authentication strategy for connecting to lds.org thru LDS Connect with Ruby / Sinatra / etc

Manages collecting of facebook authentication and provides helpers. It uses koala and is built for Rails 3.

Library utilizing IDCRL for Microsoft Windows Live ID authentication.

Locomotive plugin for adding basic authentication to pages of a site

Loginza - an interactive JavaScript widget provides visitors to your sites, a wide range of options for authentication through the accounts of common WEB-portals and services

LondonCab Authentication Client

A Gem for simplifying OpenId Authentication

A REST client for the UK Companies House API, including authentication

A mixin for Mongoid document models allowing for publishing them after authentication

Merb Slice adds quick DB'less OpenID authentication to your app

It's a combination of devise and CanCan gem and flexible to identify your modules

A super simple session-based authentication gem, for when you need to add basic admin capability to a single-user Rails app.