Kong Gateway's latest release, version 2.4, introduces a JavaScript Plugin Development Kit (PDK), allowing developers to create plugins using JavaScript due to its widespread use and robust library support. This new functionality is demonstrated through the creation of a plugin that adds the X-Clacks-Overhead HTTP header, inspired by Terry Pratchett, to all responses. The environment setup involves running a Node.js server alongside Kong Gateway, with a Docker-based environment provided for ease of use. Plugins are managed through a plugins directory, and the JavaScript PDK simplifies plugin development by automatically providing access to the necessary Kong object. The process includes enabling the plugin via configuration files and testing it locally. Developers can make the plugin behavior customizable through configuration options, such as toggling the X- prefix for headers, demonstrating the flexibility and potential of the new JavaScript PDK in enhancing Kong Gateway's capabilities.