Sails.js (or Sails) is an open-source fullstack web framework built on top of Node.js. Inspired by popular MVC frameworks such as Ruby on Rails, Sails makes it easy to build robust web-based applications. As Sails.js is an MVC framework, it provides an architecture that separates the app domain into models (data), controllers (business logic) and view (presentation).
For its views, Sail.js uses EJS (Embedded JavaScript) - a templating engine for building for building dynamic views, though Sails.js also supports using other view engines.