Various embodiments provide compatibility shims that can be utilized by a web browser to dynamically change web browser platform features per domain or website. The compatibility shims can be deployed to the web browser and updated in a manner similar to that of a webpage. In one or more embodiments, the compatibility shims can be utilized to change a browser's behavior and/or the manner in which the browser represents itself per domain or website. Further, the compatibility shims can enable the web browser to dynamically remove or change support for web platform features. In addition, in at least some embodiments, users can apply their own compatibility shims to their own list of websites or webpages.