Deterministic Matching

Deterministic matching is the process of identifying the same user across different devices using a unique and persistent identifier, such as an email address.

Because the identifier is fixed and verified — rather than inferred — the match is exact, not probabilistic. This allows advertisers, AdTech platforms, and publishers to recognize users across different devices, browsers, and channels, enabling more precise ad targeting, analytics, and attribution.

Applications that require users to sign in with an email address — such as Facebook, Google, and Twitter — can deterministically match those users whether they're on a smartphone, laptop, or tablet, since the same credential links activity across all surfaces.