A method, product, and system comprising: obtaining a webpage request from an in-app browser of an application of a user device, wherein the webpage request is configured to request a webpage or a portion thereof from a server, wherein the webpage request comprises a user-agent field; identifying that the webpage request has no valid referral information; and based on the webpage request, determining artificial referral information of the webpage request, wherein the artificial referral information indicates a referral source of the webpage request.