Node.js vs. Android SDK vs. MEAN

Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

Android provides a rich application framework that allows you to build innovative apps and games for mobile devices in a Java language environment.

MEAN (Mongo, Express, Angular, Node) is a boilerplate that provides a nice starting point for MongoDB, Node.js, Express, and AngularJS based applications. It is designed to give you a quick and organized way to start developing MEAN based web apps with useful modules like Mongoose and Passport pre-bundled and configured.