Web archives contain a wide variety of data types that depend on the right execution environment to perform correctly. Java applets, Flash, the now ubiquitous Javascript, Web Fonts, WebP images and many more are dependent on a browser environment with certain capabilities. Building on the work from oldweb.today, Webrecorder introduces containerized browsers—fixed browser versions running in a controlled environment including plug-ins which can be spun up on demand—for both recording and replay of web archives.

We will demonstrate how these environments could be described and queried as part of the context of a recording, as well as ideas for permanently stabilizing and storing them. Additional ideas presented will include discussion of a common API based on Memento that could be used to describe browser environments, as well as the latest features available in Webrecorder for collaboration and augmentation of existing web archives.