Identity resolution

Identity resolution decides which records across email addresses, device identifiers, loyalty cards and order history belong to the same person, then merges them into one profile. Get it wrong in one direction and you message the same customer three times; wrong in the other and you collapse two members of a household into one. Deterministic matching on a shared key is the safe default, while probabilistic matching adds reach and risk. Keep merges reversible and log which records were joined.