User-scoped request
Call the CPX surveys endpoint with a stable user_id. When calling server-to-server, also provide the end user’s IP and user-agent information as required by your integration.
Do not share responses across users
The CPX feed is tied to the external user mapping. Do not cache one user’s CPX survey URLs and distribute them to unrelated users.
Postback mapping
The same stable mapping is used to associate later CPX postbacks with the original publisher/visitor.