OmniAuth - A library that standardizes multi-provider authentication utilizing Rack middleware.

GitHub - binarylogic/authlogic: A simple ruby authentication solution.

A simple ruby authentication solution contribute to binarylogic authlogic development by creating an account on git hub

GitHub - thoughtbot/clearance: Rails authentication with email & password.

Rails authentication with email password contribute to thoughtbot clearance development by creating an account on git hub

GitHub - heartcombo/devise: Flexible authentication solution for Rails with Warden.

Flexible authentication solution for rails with warden git hub heartcombo devise flexible authentication solution for rails with warden

JWT - JSON Web Token implementation in Ruby.

Knock - Seamless JWT authentication for Rails API.

Monban - A very simple and extensible user authentication library for rails.

Rodauth - Authentication and account management framework for Rack applications.

Shield - Authentication protocol for use in your routing and model context.

Sorcery - Magical Authentication for Rails 4, and Rails 5.

warden - General Rack Authentication Framework.

Doorkeeper - An OAuth2 provider for Rails.

OAuth2 - A Ruby wrapper for the OAuth 2.0 protocol.