Virtual Token Descriptor for eXtensible Markup Language (VTD-XML) refers to a collection of efficient XML processing technologies centered around a non-extractive XML, "document-centric" parsing technique called Virtual Token Descriptor (VTD). Depending on the perspective, VTD-XML can be viewed as one of the following: VTD-XML is developed by XimpleWare and dual-licensed under GPL and proprietary license. It is originally written in Java, but is now available in C and C#.