Affiliate Tracking: What is the Difference Between Client-Based Tracking and Server-Based Tracking

Peter Hamilton

Affiliate tracking has come a long way in the short history of online advertising.  Industry challenges and innovative business models have stimulated the development of many technologies and methods of tracking, and as a result, there are now a number of options for tracking and reporting conversions.  Choosing the right conversion tracking method and implementing it correctly can be a little confusing, which is why I thought it was important to clarify the differences between client-based tracking and server-based tracking.

First you need to understand the basic flow of affiliate tracking.  Affiliates copy their unique tracking links from an affiliate network platform.  This link is specific to each affiliate and is used to give credit to the affiliates sending users to the offer (or advertisement).  When a user clicks an affiliate link, it is recorded as a click and information is stored about the offer, the affiliate, and the user.  If the user performs the desired action (purchases something, fills out a lead form, etc.), that stored information is then attached to a conversion.  Once you understand this concept, the best way to explain the major difference between client-based tracking and server response tracking is by explaining where that tracking information is actually stored.

Client-Based Conversion Tracking Client-Based tracking relies on storing information on the actual user’s computer by placing a cookie in the user’s browser when an advertisement is clicked.  If the user reaches the conversion page (final sale or lead), a tracking pixel that was placed on the conversion page sends the cookie information back to the tracking platform, recording a conversion for the proper affiliate.  The two most common tracking pixel formats are iFrame and Image pixels.  These are automatically generated once an offer is created in an affiliate tracking software like HasOffers.  Placing this tracking pixel on the conversion page is the only thing required of an advertiser when using client-based tracking.  For this reason, it is often the simplest way to set up conversion tracking.  The ease of setup for advertisers and low requirement of technical savvy make client-based tracking an excellent solution for many networks.

Server-Based Conversion Tracking Also known as cookie-less tracking, server-based tracking requires nothing to be placed on the user’s computer.  Many consider server-based methods to be more accurate because conversions are not lost when a user has cookies disabled on their Internet browser.  Instead of using cookies to store information, server based tracking stores information associated with the user, the affiliate, and the offer on a server and attaches it to some unique identifier.  The most common unique identifiers generated by network software are Transaction IDs and Affiliate IDs.  With server-based tracking, the advertiser is responsible for storing that unique identifier and passing it back to the tracking server when a user completes a conversion (also known as a server postback).

The diagram below shows how a transaction ID is used in a server-based tracking model.

Setting up conversion tracking can be a little tricky the first time through, but after you successfully set up the first offer, the next one will be a piece of cake.  I hope this helps clear up some confusion about conversion tracking methods and their implementation.  To learn more about affiliate tracking on HasOffers take a look at our Conversion Tracking white paper or visit the affiliate tracking technology page in the features section of

Peter Hamilton

A performance marketer by background, Peter is the CEO of TUNE, the world's leading mobile marketing platform. Peter has lead the company to 9 offices around the world and nearly 300 employees, now trusted by companies like Expedia, Starbucks, Supercell, and Uber. Follow @peterhamilton