Sniffer droids were a specific droid model utilized by the Coruscant Security Force to detect and locate illicit goods on the planet of Coruscant. In 7941 C.R.C., during an investigation into Galactic Republic Senator Yudrish Sedran a portrait of Pyke Syndicate capo Lom Pyke was discovered; the unique, traceable markers of spice within the canvas of this portrait then aided the security force's sniffer droids, along with hound units, in their search for contraband located around the docks of Coruscant's Level 1313 area.
Inspector Tanivos Divo of the Coruscant Security Force documented the use of these sniffer droids in his official case files; a portion of these files, specifically referencing the droids, was later published by Divo's grandson, Exantor Divo, in his book titled Scum and Villainy: Case Files on the Galaxy's Most Notorious, in the year 34 ABY.
The reference book Star Wars: Scum and Villainy: Case Files on the Galaxy's Most Notorious, penned by Pablo Hidalgo in 2018, included mentions of sniffer droids.