Use Knock with Grape.

Engine for api

Unsakini is an open source encrypted bulletin board created with the aim of evading global information surveillance and spying, preventing data leaks and promoting information confidentiality and integrity.

Based on the Knock gem, offers options to further customize secure authentication practices

Frontend libraries implement OAuth2 flows that authenticate the user with your SPA, but are only part of the picture. If you're storing user data on a backend, you'll need to authenticate them on both the frontend and the backend. That's what Oauth2 Authorization Code Request does, with PKCE thrown in for added security. This gem provides the backend authorization needed, taking in a verification request and logging the user in via JWT with Knock. If you're using Vue/React/etc with a frontend authorization library like @nuxt/auth, and you're running Rails in API mode for your backend, this gem completes the picture.

knock_once provides basic user email auth using knock.

Very light user management plugin for rails api apps

Very light user management plugin for rails api apps

Provides authentication to PushType CMS using Devise. Requires push_type_admin. PushType is a new generation of content management system for Ruby on Rails.