Improving revenue with user data matching

User data matching is a separate process from the main real-time bidding (RTB) auction and the ad rendering process. User Matching allows platforms within the ad technology ecosystem to map their identifiers together, typically across separate domain spaces.

While User Matching is a secondary process to RTB, it performs a critical function that has a direct, tangible benefit to publisher revenue. When Index can explicitly inform DSPs of their respective IDs through user matching, DSPs bid more frequently, and with much higher bid values. Our research indicates that DSPs bid anywhere from 5 to 12x more (higher CPMs mean more bids) when their DSP identifier is present than when it is not. Publisher monetization deeply depends on user matching because it is a critical signal for buyers, that in turn maximizes opportunities for bids, and higher bid prices.

How to add the user matching helper to your site

To set up user data matching on your site, you add the following code to all of your web pages that include an ad call to Index. The code can be placed anywhere, but it is recommended that you add the code to your footer to minimize issues with page performance and to make sure that the user matching helper runs as soon as the page is rendered.

<iframe width="0" height="0" frameborder="0" scrolling="no" src="" style="display: none;" marginheight="0" marginwidth="0"></iframe>

You can also add the code in your tag management system. For example, Google Tag Manager, Tealium, etc.

If you are integrated with Index using Prebid.js version 3.13 or later, user matching is built into the adapter and you can also enable it using the Prebid Publisher API. For more information about how to verify that it is enabled, see Verify that the user matching helper is enabled for a Prebid.js integration.

How user data matching works

With user data matching, an ad tech platform passes its user identifier to another ad tech platform through URL endpoints and call backs. This process usually occurs between an ad exchange and a DSP.


Index Exchange (Index) is working with a new DSP called Ibiza Media. With user data matching using third-party cookies, Index can map a user's cookie ID of 123 to Ibiza Media's cookie ID of ABC. When Index sees user 123 and hosts an auction on a website, such as, Index can tell Ibiza Media that user ABC is eligible for bidding. To understand how user matching works in more detail with Ibiza Media, refer to the steps below:

Index places a pixel, which is a user matching URL, on the publisher's site:$USERMACRO

Index populates the user_id value with Index's user cookie ID of 123 and sends this to Ibiza Media through a network call.

Ibiza Media populates $USERMACRO with their user cookie ID of ABC.

With user data matching, Ibiza Media can more easily match with a user they recognize and since matched users are usually valuable, the publisher can maximize on bidding opportunities and competitive bid prices.