Ensuring consistent experiment results across Client-Side Rendered (CSR) and Server-Side Rendered (SSR) pages when using Statsig involves establishing a single source of truth for user assignments. The challenge arises when independent network requests on different pages result in varying initialization times, potentially leading to different experiment variants being presented to the user.
To address this, it is recommended to have one consistent source of truth for the user's assignment. This can be achieved by using the assignments from the first page (CSR) and carrying them over to the second page (SSR), rather than initializing a new request on the second page.
This approach ensures that the user experiences a consistent variant throughout their session, regardless of the page they navigate to. It is important to note that the user's decision for any getExperiment
call is determined at the time of initialization, not when getExperiment
is called. The getExperiment
call simply returns the value fetched during initialization and logs the user's participation in the experiment and their assigned group.
To implement this, developers should ensure that the assignments are fetched from the network request on the first page and then passed to the second page, avoiding the need for another initialization request and the management of an ever-growing list of parameters.