Koa

Koa is a new web framework for NodeJS, designed by the team behind ExpressJS. Koa is a smaller, more expressive and more robust foundation for web applications and APIs. By leveraging async functions Koa means developers do not have to use call-backs and it greatly increases the ability for error-handling.

Koa does not bundle any middleware within its core, and it provides an elegant suite of methods that make writing servers fast and enjoyable.

License: Open Source (MIT)