As they say in the website, Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine that uses an event-driven, non-blocking I/O model that makes it lightweight and efficient. But what that means and why should I start using it? Let us see.
Hapi.js and Express solve the same business problem, which is providing an API for HTTP servers in Node.js. Having some conversation with the Javascript gurus at lunch, somebody mentioned Hapi.js. Once I got my eyes on it and its tutorials, it looked pretty similar to Express. Once you start looking at the documentation and examples that both of them provide, and they both have that simple javascript-ish similarity. But the deeper you dive, the more differences you find.