Is MusicXML free?
The MusicXML DTD and XSD are available under a royalty-free license from Recordare. This license is modeled on those from the World Wide Web Consortium (W3C). If you follow the terms of the license, you do not need to pay anyone to use MusicXML in your products or research. Recordare has no patents issued or pending for the MusicXML DTD and XSD.