Miku uses Yamaha Corporation's Vocaloid 2, Vocaloid 3, and Vocaloid 4 singing synthesizing technologies, and Crypton Future Media's Piapro Studio, a standalone singing 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. The voice is modeled from Japanese voice actress Saki Fujita.