Designed to support the EU General Data Protection Regulation (GDPR), this module works with supported Consent Management Platforms (CMPs) to fetch an encoded string representing the user’s consent choices and make it available for adapters to consume and process.
This module will perform its tasks with the CMP prior to the auction starting. A rough synopsis of this interaction process would be:
Fetch the user’s consent data from the CMP (see note below regarding a workflow variance for new users).
With a valid set of consent information, we will incorporate this data into the auction objects (for adapters to collect) and then allow the auction to proceed.
Note - In the the case of a new user, the CMP will respond only once there is consent information available; ie the user picked their consent choices. Given this can take some time for the average user, coupled into the module is a timeout setting.
For those unfamiliar with this timeout setting in place, the CMP will be permitted a specified amount of time to operate before it’s deemed unacceptable or it’s assumed an issue has occurred.
When either this timeout occurs or if an error from the CMP is thrown, one of two options are taken; either:
The auction is canceled outright.
The auction proceeds without the user’s consent information.
Though these options are mutually exclusive, they are configurable by the publisher via the site’s implementation of the prebid code (see further below for details) so that they can be used in the proper scenarios for that site/audience.
To utilize this module, a separate CMP needs to be implemented onto the site to interact with the user and obtain their consent choices.
The actual implementation details of this CMP are not covered by this page; any questions on that implemenation should be referred to the CMP in question. However, we would recommend to have the CMP’s code located before the prebid code in the head of the page, in order to ensure their framework is implemented before the prebid code starts to execute.
The module currently supports any CMP that conforms to the IAB standard for the 1.1 CMP spec (more info here).
Once the CMP is implemented, simply include the module in your build and add a consentManagement object in the setConfig() call. Adapters that support this feature will be able to retrieve the consent information and incorporate it in their requests.
The ID for the CMP in use on the page. Default is 'iab'
Length of time (in milliseconds) to allow the CMP to perform its tasks before aborting the process. Default is 10000
A setting to determine what will happen when obtaining consent information from the CMP fails; either allow the auction to proceed (true) or cancel the auction (false). Default is true
true or false
A Object representing the consentData being passed directly, only in used when cmpApi is ‘static’. Default is undefined. Example see the tests for consentManagement.
Example: IAB CMP using the custom timeout and cancel auction options.
Example: Static CMP using custom data passing.
The consentData object can be retrieved by a existing CMP by calling
Build the package
Step 1: Bundle the module code
Follow the basic build instructions on the GitHub repo’s main README. To include the module, an additional option must be added to the the gulp build command:
Step 2: Publish the package(s) to the CDN
Note that there are more dynamic ways of combining these components for publishers or integrators ready to build a more advanced infrastructure.
Note - for any adapters submitting changes to make themselves compliant, please also submit a PR to the docs repo to add a gdpr_supported: true variable to your respective page in the bidders directory. This will have your adapter’s name automatically appear on the list of GDPR compliant adapters (at the bottom of this page).
To find the GDPR consent information to pass along to your system, adapters should look for the bidderRequest.gdprConsent field in their buildRequests() method.
Below is a sample of how the data is structured in the bidderRequest object:
Notes about the data fields
This field contains the user’s choices on consent, represented as an encoded string value. In certain scenarios, this field may come to you with an undefined value; normally this happens when there was an error during the CMP interaction and the publisher had the config option allowAuctionWithoutConsent set to true. If you wish to set your own value for this scenario rather than pass along undefined to your system, you can check for the undefined value in the field and replace it accordingly. The code sample provided in the consentRequried section below provides a possible approach to perform this type of check/replacement.
This field contains the raw vendor data in relation to the user’s choices on consent. This object will contain a map of all available vendors for any potential adapters that may wish to read the data directly. One use-case for reading this data could be if an adapter wished to be omitted in a request if they knew if consent wasn’t given for them. Adapters will need to read through the object to find their appropriate information.
This boolean represents if the user in question belonged to an area where GDPR applies. This field comes from the CMP itself; it’s comes included in the response when a request is made to the CMP API. In the odd chance for some reason this value isn’t defined by the CMP, each adapter has the opportunity to set their own value for this field.
There are two general approaches that can be taken by the adapter to populate this field:
Set a hardcoded default value.
Using their own system, derive if consent is required for the end-user and set the value accordingly.
Using the former option, below is an example of how the integration could look:
The implementation of the latter option is up to the adapter, but the general premise should be the same. You would check to see if the bidderRequest.gdprConsent.gdprApplies field is undefined and if so, set the derived value from your independent system.
If neither option are taken, then there is the remote chance this field’s value will be undefined. As long as that acceptable, this could be a potential third option.
The gdprConsent object is also available when registering userSync pixels. The object can be accessed by including it as an argument in the getUserSyncs function in the following manner:
Depending on your needs, you could potentially either include the consent information in a query of your pixel and/or given the consent choices determine if you should drop the pixels at all.
Publishers not using an IAB-Compliant CMP
Prebid.js and much of the ad industry rely on the IAB CMP standard for GDPR support, but there are some publishers who may have
implemented different approach to meeting the privacy rules. Those publishers may utilize Prebid.js and the whole header bidding ecosystem if they build a translation layer between their consent method and the IAB method.
At a high level this looks like:
build a window.__cmp() function which will be seen by Prebid
build a message receiver function if safeframes are in use
format consent data in a string according to the IAB standard
Below is sample code for implementing the stub functions. Sample code for formatting the consent string may be obtained here.