Introduction to Undertow

Undertow is a web server designed to be used for both blocking and non-blocking tasks. Some of its main features are:

  • High Performance

  • Embeddable

  • Servlet 4.0

  • Web Sockets

  • Reverse Proxy

There and two main ways that Undertow can be used, either by directly embedding it in your code, or as part of the Wildfly Application Server. This guide mostly focuses on the embedded API’s, although a lot of the content is still relevant if you are using Wildfly, it is just that the relevant functionality will generally be exposed via XML configuration rather than programatic configuration.

The documentation is broken up into two parts, the first part focuses on Undertow code, while the second focuses on Servlet.