Ractive.js is described as 'template-driven UI library that transforms your templates, styles and logic into blueprints for highly interactive apps. Ractive.js works for you, not the other way around. You do not need to learn new terminologies, concepts, and methodologies' and is an app in the Development category. There are more than 50 alternatives to Ractive.js for a variety of platforms, including Mac, Windows, Linux, Online / Web-based and Self-Hosted solutions. The best alternative is React, which is both free and Open Source. Other great apps like Ractive.js are AngularJS (Free, Open Source), ExpressJS (Free, Open Source), Meteor (Free, Open Source) and Polymer (Free, Open Source).
Polymer is a library that uses the latest web technologies to let you create custom HTML elements. Build anything from a button to a complete application as an encapsulated, reusable element that works across desktop and mobile.
You can write less code with Ember's Handlebars integrated templates that update automatically when the underlying data changes. Ember.js incorporates common idioms so you can focus on the development of your application ( and not reinventing the wheel ).