miku uses yamaha corporation's vocaloid 2, vocaloid 3 and vocaloid 4 vocal synthesis technologies. she also uses crypton future media's piapro studio, a stand-alone vocal synthesizer editor. she was the second vocaloid sold using the vocaloid 2 engine and the first japanese vocaloid to use the japanese version of the 2 engine. her voice is based on that of japanese actress saki fujita.