Stage 03 of 07 · Identity across the lifecycle
Unify is where multiple identifiers — email, loyalty ID, device ID, CRM contact ID — collapse onto a single golden record. The hard part isn't performing the merge once; it's making the merge survive the identifiers changing later, without silently reversing months of unification.
Last reviewed 27 Sept 2026
The merge
Two profiles merge on a shared email. Six weeks later the customer changes that email in one brand's account centre and the merge silently reverses, splitting order history back across two records.
Tell — you find out when a customer is told two different things by two different channels.
What resolved looks like
Merge keys are ranked and the relationship between identifiers is modelled explicitly — not re-inferred fresh on every sync — so a changed email doesn't unwind six months of unification. SAP CDP, Adobe RT-CDP and BlueConic all support this; it has to be configured deliberately.
Systems that read this stage — SAP CDP · Adobe RT-CDP · BlueConic
golden_idmerge_keyidentifiers