DUY is a Barcelona-based audio software developer that helped pioneer the plug-in market. The company traces back to a recording studio founded in 1986 in Spain, and began developing digital signal processing tools in 1997, becoming one of the earliest third-party developers for Digidesign's TDM and AudioSuite formats on Pro Tools. Its tools are now offered in native VST, AU, and AAX formats alongside legacy TDM versions.

The brand is best known for its early work in modeling analog behavior in the digital domain. DaD Tape was among the first plug-in simulators of analog tape saturation, and DaD Valve was an early plug-in emulation of tube/valve coloration. Other notable titles include MagicEQ and Magic Spectrum (a mastering and spectrum-matching tool), DUY Shape (a hybrid dynamics/EQ/enhancer processor), DUY Wide for stereo imaging, DUY Silence for noise reduction, LucidVerb convolution-hybrid reverb, Dream Dynamics, and the MAX DUY loudness/limiting tool. Many of these are also packaged in bundles such as the Essentials, Producer's, Gold, and Platinum collections.

DUY's plug-ins have circulated in mixing and mastering rooms since the late 1990s, and the company is often grouped with the original wave of TDM-era developers alongside names like Sony Oxford, Waves, and Focusrite. The DUY name is shared with — but operationally separate from — the studio of Spanish electronic musician Michel Huygen (Neuronium).

DUY has 2 products cataloged on Equipboard, including Saturation Plugins. Their gear is featured by 2 artists, with the strongest followings in Electronic, Pop, and Rock. Notable users include Rihanna and Craig Potter.