GSi (Genuine Soundware and Instruments) is an Italian software developer specializing in virtual instruments and audio effect plugins for music production. Founded by Guido Scognamiglio, who serves as the primary programmer, the company focuses on emulating classic keyboards and other acoustic and electromechanical instruments using proprietary sound engines, including their WLF (Wavetable Linear Format) sampling technology.

The brand is best known for its tonewheel organ emulations, particularly the VB3 and its successor VB3-II, which model Hammond B3-style American electromagnetic organs as well as Italian transistor organs of the 1970s. Their catalog also includes MagicTines (electric piano), Model D6 (physical-modeling Clavinet), JustPiano, SoloTrumpet, Mini Orchestra, and the Drum-80 drum machine, alongside effects plugins such as GSiRotary, GS-201mk2, and TimeVerb-X. Plugins are available for Windows, macOS, and iPad.

GSi also collaborates on hardware through V.M. Connection and has been associated with the Crumar instrument line, extending its organ and keyboard emulation expertise into dedicated stage instruments.

Genuine Soundware has 4 products cataloged on Equipboard, including Virtual Instrument and Delay Plugins. Their gear is featured by 3 artists, with the strongest followings in Electronic, Rock, and Pop. Notable users include Paul 'Wix' Wickens, Huxley, and Niko The Kid.