Abstract: Content providers may wish to display different versions of content to different users, which may require different versions of the content to be deliverable. The assignment of a particular version of the content to a particular user may also need to persist over time for that particular user. It may be desirable that this functionality occurs at an edge server of a content delivery network, rather than at an origin server. In some embodiments, the edge server may receive a user request including a user identifier for content from a user device; identify an experiment key for the user request based at least in part on the user identifier, the experiment key associated with an experimental version of the content; and transmit an experiment fetch request including the experiment key to an edge cache to retrieve the experimental version of the content.