Undertow is a flexible performant web server written in java, providing both blocking and non-blocking apis based on nio.

undertow has a composition based architecture that allows you to build a web server by combining small single purpose handlers. this gives you the flexibility to choose between a full java ee servlet 3.1 container, or a low level non-blocking handler, to anything in between.

undertow is designed to be fully embeddable, with easy to use fluent builder apis. undertow??s lifecycle is completely controlled by the embedding application.