Express

Build practical, production-ready Node.js apps in a matter of weeks, not months. Sails is the most popular MVC framework for Node.js, designed to emulate the familiar MVC pattern of frameworks like Ruby on Rails, but with support for the requirements of modern apps, data-driven APIs with scalable, service-oriented architecture. Sails makes it easy to build custom, enterprise-grade Node.js apps. Building on top of Sails means your app is written entirely in JavaScript, the language you and your team are already using in the browser. Sails bundles a powerful ORM, Waterline, which provides a simple data access layer that just works, no matter what database you're using. Sails comes with blueprints that help jumpstart your app's backend without writing any code. Since Sails translates incoming socket messages for you, they're automatically compatible with every route in your Sails app. Sails offers commercial support to accelerate development and ensure best practices in your code.

As an asynchronous event-driven JavaScript runtime, Node.js is designed to build scalable network applications. Upon each connection, the callback is fired, but if there is no work to be done, Node.js will sleep. This is in contrast to today's more common concurrency model, in which OS threads are employed. Thread-based networking is relatively inefficient and very difficult to use. Furthermore, users of Node.js are free from worries of dead-locking the process, since there are no locks. Almost no function in Node.js directly performs I/O, so the process never blocks except when the I/O is performed using synchronous methods of Node.js standard library. Because nothing blocks, scalable systems are very reasonable to develop in Node.js. Node.js is similar in design to, and influenced by, systems like Ruby's Event Machine and Python's Twisted. Node.js takes the event model a bit further. It presents an event loop as a runtime construct instead of as a library.