dm-devise adds MongoMapper support to devise (http://github.com/plataformatec/devise) for authentication support for Rails

Rodauth extension for logging in and creating account via OmniAuth authentication.

omniauth provider for Microsoft V2 Authentication

NoPassword is a Ruby on Rails gem that allows session authentication with a token or a magic link via an email sent to the user; there is no need for a password.

Tachiban provides simple password hashing for user authentication with Argon2 for Hanami web applications.

MYOB authentication strategy for OmniAuth

Simple way to customize devise authentication logic and still be inline with all other devise parts

Authenticates requests proxied by a bitly/oauth2_proxy server using shared-secret HMAC request signatures.

Opinionated minimal Rails authentication scaffolding with Hotwire, React, or Vue + Tailwind.

The APIMatic Core libraries provide a stable runtime that powers all the functionality of SDKs. This includes functionality like the ability to create HTTP requests, handle responses, apply authentication schemes, convert API responses back to object instances, and validate user and server data.

Gem for Rails application - provides you list of online users (for authentication gem 'devise')

Supports: Admin user bind operation, Regular user authentication, Create (add), read (search), update (modify), and delete operations for users and groups

This extension provides PAM - Pluggable Authentication Modules - integration

The Google Sign-In API gives OAuth2 JSON Web Tokens (JWT) as response data upon user sign-in. A necessary step for a service provider to trust such a token is validatation. Accepting the token without validation would allow a malicious client to simply assert itself in your system. ...

Omniauth plugin for Artsy authentication.

Authentication for Rails applications

A ready-to-go application with authentication, authorization, logging... with bootstrap flavor

Simple and modulable authentication gem

A minimal dependency library for interacting with a Cerner OAuth 1.0a Access Token Service for invoking Cerner OAuth 1.0a protected services or implementing Cerner OAuth 1.0a authentication.

Rack middleware for using the Authorization header with token authentication