User Matching (also called User Syncing or Cookie Syncing) is a method for sharing cookie-based user data between different servers. In Adzerk, user matching is most commonly used to match a UserKey in UserDB with the User ID of an RTB provider.
Since cookies can only be read and written by their originating domain, servers need to make requests to each other to share a cookie's contents. The User Matching pixel bridges the gap between an RTB provider and Adzerk by passing the contents of a user's cookie from the RTB provider to UserDB.
The pixel can be called from any page: by the third party service, by the Adzerk customer, or by Adzerk.
RTB providers such as Index Exchange require their User ID (Index ID) passed with the Adzerk ad request. Otherwise, Index won't have access to that user's targeting data, leading to lower bids and lower publisher revenue.
- An Adzerk customer should construct the user matching pixel for their provider:
The pixel's URL requires a
partnerId (the ID of the RTB provider in Adzerk) and an empty placeholder for the
userId (the demand partner's identifier for this user).
userIdis the ID of the user for the bidder. It is not the Adzerk
userKeyfor the user.
The demand partner will append their user identifier to this string before invoking it on the Adzerk servers.
Note that other query parameters can be added before the
userIdparameter to pass data to the RTB provider.
If you don't know the
partnerIdof the RTB partner, contact Adzerk support.
- URL-encode the Adzerk pixel. Append Adzerk's pixel to the end of the user matching endpoint of the provider and place that call on your page. For example, using Index Exchange's pixel:
- Index's service will look up the User ID from their own cookie in the user's browser. Index will then append that User ID to the end of the URL and redirect to the Adzerk pixel:
After that pixel is fired in the browser, Adzerk will write the value of the User ID to the user's record in UserDB. (Adzerk knows the user's UserDB User Key from on the
azkcookie set with each request.)
The next time Adzerk makes an OpenRTB call to Index, we will pass in Index's User ID via UserDB.
The domain of the user matching pixel (such as
e-1234.adzerk.net) must be the same domain where you request ads. Otherwise user matching will not work.
For example, if you have white-labeled the Adzerk ad domain to something like
adz.mycompany.com, then you must use that white-labeled domain in the user matching pixel.
Updated 10 months ago