Rapidoid vs Undertow: What are the differences?
Rapidoid: No-Bullshit Web Framework for Java. Rapidoid consists of several de-coupled modules/frameworks which can be used separately or together: http-fast, gui, web, fluent, u, and more; Undertow: A flexible performant web server written in java. It is a flexible performant web server written in java, providing both blocking and non-blocking API’s based on NIO. It has a composition based architecture that allows you to build a web server by combining small single purpose handlers. The gives you the flexibility to choose between a full Java EE servlet 4.0 container, or a low level non-blocking handler, to anything in between.
Rapidoid and Undertow are primarily classified as "Frameworks (Full Stack)" and "Web Servers" tools respectively.
Rapidoid is an open source tool with 1.42K GitHub stars and 136 GitHub forks. Here's a link to Rapidoid's open source repository on GitHub.