Virtual Studio Technology (VST) is developed by Steinberg and first launched in 1996. The SDK/API is freely available to all.
VST creates a full, professional studio environment on your PC or Mac. VST allows the integration of virtual effect processors and instruments into your digital audio environment. These can be software recreations of hardware effect units and instruments or new creative effect components in your VST system. All are integrated seamlessly into VST compatible host applications. These VST modules have the sound quality of the best hardware units, yet are far more flexible. All functions of a VST effect processor or instrument are directly controllable and automatable; either with a mouse or with an external hardware controller. VST also allows easy integration of external equipment, allowing you to put together a system tailor-made to your needs.
Being an open standard, the possibilities offered by VST have steadily been growing over the past decade. New virtual effect processors and virtual instruments are constantly being developed.