All about cross-domain and cross-subdomain consent sharing within the Consent Studio platform
The state of this feature
This information was last updated on April 1st, 2025
Cross-domain sharing, from our point of view, can be divided into two areas:
Sharing consent across different top level domains → cross-domain consent sharing
Sharing consent within the same top level domain → cross-subdomain consent sharing
Currently, we only offer the latter feature.
How does cross-subdomain consent sharing work?
Scenario
Let's assume we have a domain example.com. Apart from a product website on example.com, this site also has two subdomains: app.example.com and docs.example.com.
To provide an uninterrupted and seamless experience for the website visitor, it is a good practice to not show a new consent banner on each and every domain.
Solution
When a user's first interaction with your domains is on app.example.com and they move to example.com in a later stage, the consent given on app.example.com will be shared across all the example.com domains. This prevents a new banner from being shown on each subdomain.
For each domain that is known to us (see requirements below), we will update or create a consent cookie when consent is provided.
The consent cookie is our client-side storage of a user's consent and enables us to maintain fast script loading.
This is automatically handled by the Consent Studio consent banner. However, there are requirements to be met and limitations to be considered.
Requirements
We can only set the consent cookie for domains that we know. Therefore, the top level domain must be registered with Consent Studio and the subdomains must either:
...be registered as separate domains in the Consent Studio dashboard (if you would like our automatic scanner to discover the cookies used on the given subdomain);
...or registered as domain aliases of the top level domain (we will not automatically discover cookies on this domain and the cookie list of the top level domain will be used).
A Consent Studio subscription must be active on every domain (unless you are taking the aliases path).
There are requirements for domain aliases by default:
A domain alias may not start with
www.;A domain alias must contain two periods;
A domain alias may not already be claimed by another top level domain;
A domain alias must end with the top level domain that it is being added to.
The www. subdomain is already covered by our platform for all top level domains. This means that you do not need to add it as an alias.
Good to know: the requirements for subdomains can be lifted by our customer service team in specific cases. Feel free to contact us by e-mailing support@consent.studio.