Third-party cookie deprecation labels

As part of Chrome-facilitated testing , Chrome provides testing modes that allow sites to preview site behavior without third-party cookies. To help bidders test, bid requests contain Chrome's cookie deprecation labels. Bidders can also use pretargeting to filter for requests that contain cookie deprecation labels.

For information on how Google Ad Manager handles cookie deprecation labels, see the Google Ad Manager Help Center.

Bid Request

Google Authorized Buyers bid request protocol

Chrome's cookie deprecation label is represented in the cookie_deprecation_label field in the BidRequest.Device message. This field is available in the open beta version of the protocol.

Here's the definition:

message BidRequest {
  message Device {
    // Chrome-facilitated cookie deprecation testing label as provided by
    // Chrome.
    optional string cookie_deprecation_label
  optional Device device

OpenRTB Protocol

Chrome's cookie deprecation label is provided in the OpenRTB BidRequest.device.ext message. Here is the definition:

message DeviceExt {
  // Chrome-facilitated cookie deprecation testing label as received from
  // Chrome.
  optional string cdep;


Here's an example of how Google Authorized Buyers and OpenRTB protocols represent Chrome provided labels. If Chrome returns label_only_3:

Google Authorized Buyers protocol BidRequest:

device {
  cookie_deprecation_label: "label_only_3"

OpenRTB BidRequest:

  "device": {
    "ext": {
      "cdep": "label_only_3"

This extension is available in the open beta version of the protocol.


The presence of Chrome deprecation labels in the bid request is subject to existing privacy protections and controls. For example, the Chrome provided labels are unavailable if the user opts out of personalized advertising.

Pretargeting dimension

Bidders can set a new pretargeting dimension on the pretargeting configuration to filter for the requests that have Chrome labels . Each pretargeting configuration can contain one or more labels.

The supported labels are:

Mode Labels
  • control_2
  • treatment_1.1
  • treatment_1.2
  • treatment_1.3
  • control_1.1
  • control_1.2
  • control_1.3
  • control_1.4
  • label_only_1
  • label_only_2
  • label_only_3
  • label_only_4
  • label_only_5

For example, if a pretargeting configuration has [label_only_3, label_only_4], then the pretargeting configuration matches when a request contains either label_only_3 or label_only_4.