“1400 / 999 Freestyle” is a long-awaited collaboration with melancholic rapper, Juice WRLD. Both 1400 and 999 are used on the song title as these numbers represent both Trippie and Juice, respectively.

Trippie released a short snippet of this song on his story on October 10, 2018. In September 2018, The NoJumper YouTube channel also included a short snippet, in addition to the making of the song in a vlog, as both Juice and Trippie are shown listening to the song.