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User Opt-Out

Many different publishers and advertisers use UID2. Different publishers might have different opt-out processes for their individual sites; however, UID2 as a whole has very specific opt-out processes that all UID2 participants are expected to honor.

How Users Can Opt Out of UID2

Within the UID2 ecosystem, there are two types of opt out:

  • Opt out of the participant's site
  • Opt out of UID2

Because each participant has their own opt-out workflow, participants are mandated to respect a user's opted-out status and therefore not create a UID2 for any user who opted out from the participant.

For example, if a user opts out of a publisher's site, but has not opted out of UID2, the publisher should not generate a UID2 token for that user.

Consumers can always opt out of UID2 completely in the Transparency and Control Portal. Choose email address or phone number, enter the data, and follow the prompts.


To opt out both your email address and your phone number, do them one at a time.

Difference Between Opting Out from a Single Participant and Opting Out of UID2

If a consumer opts out from a specific participant, UID2 guidelines mandate that the participant no longer uses that consumer's information to create or generate a UID2, because the consumer opted out of that site specifically. Those are the requirements of the UID2 framework.

In addition, if a user opts out from a specific participant, that information is not relayed to UID2. Opting out from a specific participant does not opt a consumer out of UID2.

The sure way for a consumer to fully opt out of UID2 is in the Transparency and Control Portal.

Opt-Out Workflow

When a consumer opts out of UID2, that individual's UID2 is no longer accepted for targeted advertising anywhere in the UID2 ecosystem. However, because there is a delay in the time it takes to process and refresh UID2 information, the UID2 for a user who has opted out might be in play for a short while after opt-out. As each participant periodically refreshes their UID2s, the opt-out information is propagated to the participants.

The following steps provide a high-level outline of the workflow intended for users who engage with publishers or their identity providers.

  1. Users visit the Transparency and Control Portal, where they can globally opt out of UID2.

  2. The Transparency and Control Portal sends the opt-out request to the UID2 Operator Service.

  3. If the user has opted out, the UID2 Operator Service distributes the opt-out information to UID2 participants, as follows:

    ParticipantDistribution Method
    PublishersA publisher calling POST /token/generate with the required optout_check parameter set to 1, or POST /token/refresh, receives the opt-out response instead of the UID2 token.
    DSPsThe UID2 Operator Service distributes information on all opted-out users to DSPs via a webhook provided for the purpose. For details, see Honor User Opt-Outs.
    DSPs can also check the opt-out status of raw UID2s using the POST /optout/status endpoint.
    Advertisers and data providersThe UID2 Operator Service distributes opt-out information to advertisers and data providers via the POST /identity/map endpoint. Another option is to check the opt-out status of raw UID2s using the POST /optout/status endpoint.
    SharersUID2 sharers can check the opt-out status of raw UID2s using the POST /optout/status endpoint.

This workflow allows users to consent to the creation of UID2 identifiers and manage their UID2 consent and privacy settings through the Transparency and Control Portal.

User Trust Workflow