Tesseract began recording the album in 2017, releasing its first single, "Smile", on 23 June, with the intention of reworking it for Sonder.

Sonder marks Tesseract's second consecutive release and third overall with the original vocalist, Daniel Tompkins, who first appeared on their debut studio album, One (2011), and later, Polaris.

A concept album, Sonder was described by Tompkins as "exploring a deep and devouring sense of insignificance".

[8] "Smile" was released by the band on 23 June 2017, and was described as their "most collaborative track in recent times",[6] but was intended to be reworked and extended for the album.

For the first time, the band acquired the talents of a choir, produced and conducted by Randy Slaugh of White Moth Black Butterfly and recorded at Soularium Studios in the U.S. [9][10][11] Sonder is the band's shortest studio album at 36 minutes in length.