Kappalizer is a Chrome add-on developed by Tomas Gold that allows users to easily add color marks to web pages based on the environment they are in. Whether it's development, staging, production, or any other environment, Kappalizer makes it simple to visually differentiate between them.

With Kappalizer, you have the ability to customize the CSS styles and colors used for each environment. This means you can choose the colors that best represent each environment and easily identify which environment you are currently working in. This can be especially helpful for developers and testers who often work in multiple environments and need a quick visual reference.

The add-on is free to use and is available for the Chrome browser. It falls under the "Add-ons & Tools" subcategory of the "Browsers" category. Kappalizer is a useful tool for anyone who needs to work with different web page environments and wants to easily distinguish between them using color marks.