Matching users using netID

netID is a single sign-on platform powered by the European netID Foundation (ENID), where users can log in to various internet services and publisher sites. netID’s single sign-on allows users to provide consent and control personal data transmission across eligible partners.

Publishers can activate addressability by enabling the netID Real Time Identity (RTI) adapter in their IX Library™. With the adapter enabled, the netID identifier is added to bid requests for eligible users. In addition to providing people-based addressability that is consent aware, the adapter also helps minimize the need for DSPs to rely on third-party cookie syncing to identify users. To enable the netID adapter, see Enable a Universal ID provider in the IX Library.

DSPs that request to receive the netID identifier in bid requests can increase match rates between the DSP and Index, allowing buyers to identify more users and serve relevant ad campaigns. To support receiving the netID identifier in bid requests, DSPs must update their bidding algorithm and request Index to get on the allowed list. For more information on how DSPs can receive the netID identifier, see Receive Universal IDs in bid requests.

How IX Library passes netID identifiers

When a user logs in through netID and consents to sharing their data on an IX Library publisher site using the netID adapter, the IX Library can pass the user’s unique netID identifier to eligible DSPs.

To understand how we pass the netID identifier in IX Library, refer to the workflow below:

How netID's Universal ID is passed. Steps are detailed below.

The user's netID identifier, tpid, is created when the user provides consent in the following ways (in any order):

  • The user logs in to netID using an email address and password. The user consents to the publisher sending their personal data to for each device.
  • The user visits an Index publisher website with a CMP and consents to share their personal data through the CMP. The publisher establishes a TCF consent string for netID.

netID stores tpid in the browser's local storage.


When a user has provided consent and visits a website with the netID adapter enabled, the netID adapter checks the browser's local storage for the user's tpid using IX Library. If tpid is present, the workflow continues to step 6. If tpid is not present, the workflow continues to steps 4 and 5.

To get tpid, the IX Library sends a GET request that includes the publisher's tapp_id (netID identifier) to the netID endpoint.

  1. If netID returns tpid to IX Library in more than the allocated demand start time which is the time to generate the bid request, IX Library stores this in the browser’s local storage for subsequent page loads.
  2. If netID returns tpid to IX Library in under the allocated time to demand start time the workflow continues to step 6. IX Library also stores tpid in the browser's local storage for subsequent page loads.

IX Library makes tpid available to Index's ad server and all other certified bidding adapters.

Index and bidding adapters pass tpid using IX Library in the bid request to the allowed list of DSPs.