What are some alternatives?
When comparing Gem.js and React, you can also consider the following products
Vue.js - Reactive Components for Modern Web Interfaces
Okta - Enterprise-grade identity management for all your apps, users & devices
Svelte - Cybernetically enhanced web apps
Auth0 - Auth0 is a program for people to get authentication and authorization services for their own business use.
Preact.js - Preact is a fast 3kB alternative to React with the same modern API. Components & Virtual DOM.
OneLogin - On-demand SSO, directory integration, user provisioning and more