I will be publishing a link to my survey inside our customer web portal. Customers will be presented a link to the survey after logging in, and we would like to send the individual login data to Qualtrics when they click the link>take the survey.. 

I have been told query strings will not work as they are not dynamic and cannot accomodate a changing field value, and that this may be able to be accomplished with custom code. 

Does anyone have any experience or direction on how to ingest dynamic data via one survey url?