Privacy-safe clean-room audience overlap match
Server-to-server primitive that measures the shared-audience overlap between the tenant (party) and a partner / advertiser (partner) WITHOUT either side exchanging cleartext PII. Each side supplies cleartext records (email / phone — hashed and consent-gated server-side) and/or locally-computed hashed_identifiers (SHA-256 over the documented normalization contract, the privacy-safe path a partner uses). Returns overlap size, per-side match rate, Jaccard similarity, and the matched intersection digests that can seed an ad-audience activation — the requester only ever receives digests it already submitted, so it learns nothing about the counterparty’s non-overlapping members. k-anonymity suppression withholds every quantitative field when the overlap is below the effective min_match_threshold (default 50, floor 1), blocking the singleton-probe attack. No cleartext leaves the process and nothing is persisted; the audit log records counts only. This is an API-only surface (no dashboard UI). Owner / admin / developer with the contacts:read scope.
Response
Successful response.