Express is a simple web application framework for building hybrid web applications. You can render web pages, generate  customized responses and create user-friendly APIs quickly with ease. It just fits the trade with Node.js.

This post covers the installation and hello world example:

Installation:

buntu@ubuntu:~$ sudo npm install express
express@3.1.0 node_modules/express
├── methods@0.0.1
├── fresh@0.1.0
├── cookie-signature@0.0.1
├── range-parser@0.0.4
├── buffer-crc32@0.1.1
├── cookie@0.0.5
├── debug@0.7.2
├── commander@0.6.1
├── mkdirp@0.3.3
├── send@0.1.0 (mime@1.2.6)
└── connect@2.7.2 (pause@0.0.1, bytes@0.1.0, formidable@1.0.11, qs@0.5.1)

Hello World Example:

In the above example:

• 1. express module is imported and application object is created
• 2. Object’s get() method is called and callback is set to respond with ‘hello world’
• 3. When user sends a GET request at port 3000, an event is generated that is handled by callback function(request, response)