Experience Cloud ID Service and iFrames (whitelistParentDomain and whitelistIframeDomains)

Hi all,

struggling a little bit to set up the Visitor ID sync between parent frame and iFrames by configuring whitelistParentDomain and whitelistIframeDomains.

Background: we have two domains, domainA.com and domainB.com .

• both domains run their own Launch property
• both use the same AdobeOrgID
• both track into the same Adobe Analytics Report Suite
• third-party (demdex) cookies are disabled

Now, we want to make sure the ECID is synched across outer frame and iframe for a stitched view on the visitor.

Outer Launch property Experience Cloud ID Service config: (whitelistParentDomain is added, so it should be able iframes from the same domain, open for discussion if needed)

Data Element “whitelistIframeDomains”:

return [
    "www.domainB.com"
];

iFrame Launch property Experience Cloud ID Service config: (note that the consent is disabled by default / for testing, but don’t work with consent enabled for both, either)

However, the sync never seems to work, and the iFrame always writes its own AMCV cookies.

Has anyone ever managed to get this to work?

Are there known race conditions / timing issues which could explain the malfunction?

e.g.,

• if the iFrame is super lightweight and polls the information from the outer frame, one could imagine that the Launch property may not have fully initialized the Visitor Service?
• I do not think that the outer frame pushes anything into the iframes, right. And would the iFrame even aware of that it is running in an iFrame and would potentially delay its calls until it is certain that the outer frame won’t return a Visitor ID

It would be great to get this to work, since using 3rd party cookies does not feel like the right way to go in 2026. This feature seems to have been around for a long time, but the number of threads here is very low. So either it’s a hidden feature, or everyone else manages to get it to work xD