The document discusses tools for building web applications, including Express.js, Underscore.js, and Backbone.js. Express.js is described as providing routing, request and response rendering, and middleware capabilities. Underscore.js is a utility library that provides functions for tasks like mapping, filtering, and grouping data. Backbone.js implements a client-side MVC pattern and allows binding data to views so that changes to data automatically update views. EJS is mentioned as a templating engine that allows embedding JavaScript in HTML.