Hatsune Miku (初音ミク) is a humanoid persona voiced by a singing synthesizer application developed by Crypton Future Media. She uses Yamaha Corporation's Vocaloid 2 and Vocaloid 3 singing synthesizing technologies. She also uses Crypton Future Media's Piapro Studio, a singing synthesizer VSTi Plugin. She was the second Vocaloid sold using the Vocaloid 2 engine, and the first Japanese Vocaloid to use the Japanese version of the Vocaloid 2 engine. Her voice is sampled from Japanese voice actress, Saki Fujita. Hatsune Miku has performed at her concerts onstage as an animated projection. Hatsune Miku is portrayed to be a 16-year-old girl with long turquoise pigtails.

Vocaloid (ボーカロイド Bōkaroido) is a singing voice synthesizer. Its signal processing part was developed through a joint research project led by Kenmochi Hideki at the Pompeu Fabra University in Barcelona, Spain in 2000 (the same team that later founded Voctro Labs) and originally was not intended to be a full commercial project. Backed by the Yamaha Corporation, it developed the software into the commercial product "Vocaloid." The software enables users to synthesize singing by typing in lyrics and melody. It uses synthesizing technology with specially recorded vocals of voice actors or singers. To create a song, the user must input the melody and lyrics.