The score for the film was credited to Arcade Fire, with additional music by Owen Pallett. Arcade Fire's Will Butler and Pallett were the major contributors.[35] At the 86th Academy Awards, the score was nominated for Best Original Score.[36] In addition to the score, Arcade Fire also wrote the song "Supersymmetry" for the film, which also appears on their album Reflektor. The melody for the song from the same album, called "Porno", can also be heard during the soundtrack.[37] Yeah Yeah Yeahs frontwoman Karen O recorded the song "The Moon Song", a duet with Vampire Weekend frontman Ezra Koenig, which was nominated for an Academy Award for Best Original Song.[38]
Initially, the soundtrack had not been released on digital or physical form.[39] A 13-track score was made available for streaming online in January 2014, before being taken down.[39][40] During an "Ask Me Anything" (AMA) on Reddit on June 17, 2016, Will Butler mentioned the possibility of a future vinyl release.[41] Finally, on February 10, 2021, Arcade Fire announced that the score would be available for the first time digitally, on white-colored vinyl, and on cassette on March 19, 2021.[42]
When Theodore requests a "melancholy song" from his virtual assistant on his way home from work, a song with the lyrics "When you know you're gonna die it isn't easy" is initially played, a fragment especially composed and recorded by Arcade Fire for this scene; Theodore then aborts by saying "next" and Off You by The Breeders is played instead.
