Rakuten's server-to-server tracking works similarly to other affiliates’ s2s tracking (we already have blog posts and tags for Awin, Impact, Refersion, Outbrain, and Taboola). 

When a customer clicks on an affiliate link, their click is tracked and stored as a first-party cookie in the user’s browser. When the customer completes a purchase, the order information is passed back to the Rakuten server, with the click ID from cookies and order parameters configured in sGTM. 

Then Rakuten uses server GTM data to attribute the sale to the correct affiliate. This process happens without the need for 3rd party cookies, making it more accurate and reliable since 1st party cookies are longer live.

Useful Links:

  1. Rakuten server-to-server tracking.

  2. How to set up server-side affiliate tracking using server Google Tag Manager.