Mobile Fortify is used by ICE and CBP officers to identify people during street encounters. An officer photographs the person; the image is sent to CBP's Traveler Verification Service -- the same infrastructure used for airport processing -- and compared against government-held images. If no facial match returns, the app allows contactless fingerprint capture against IDENT, the largest biometric repository in the US government. It reportedly also supports a 'Super Query' searching databases covering individuals, vehicles, aircraft, vessels and addresses simultaneously.

The defining difference from a typical police watchlist check is the gallery: Mobile Fortify queries border and travel biometric infrastructure built for a different purpose, meaning it includes people who have never been arrested and in many cases have never crossed a border under suspicion of anything. A Privacy Threshold Analysis states individuals are not offered the chance to decline or consent to collection, that images and fingerprints are retained for 15 years including non-matches, and that the app may be used regardless of a person's citizenship or immigration status.

Its existence was first reported by 404 Media via leaked internal emails. It operates federally, which means it is not subject to the 20-plus US city and state laws banning local police use of facial recognition -- a federal officer using Mobile Fortify in a city that has banned the technology for its own police is not covered by that ban.