A plug-in effects processing engine for DAW software that was created by Steinberg. The VST engine works with the VST-enabled host software to allow audio and MIDI effects processing, synth and sampled sound modules, and mastering tools to run in real time with multitrack digital audio, operating in a fashion similar to how the auxiliary sends on an outboard mixer work, in that you can assign plug-ins to a channel (or channels) of audio or MIDI in the host VST audio recording/editing software. VST has become arguably the most proliferated plug-in engine for DAW software, mainly because of Steinberg’s support for third-party development and also due to the fact that VST plug-ins are developed for both the Mac and Wintel platforms (note that they are not interchangeable with one another; they are also not compatible with any other plug-in engine). Aside from the wealth of high-quality retail plug-ins, there are also shareware and freeware VST plug-ins offered in a plethora of locales around the web.