2017: First mixtape, 3Days, Stray Kids and Horizon
On January 18, 2017, they uploaded their first mixtape, J:/2017/mixtape, on SoundCloud, consisting of seven tracks. On August 16, 2017, they uploaded their second mixtape, 3Days, on SoundCloud as well, consisting of nine tracks. Before this, they were announced to be a part of a JYP's survival show titled Stray Kids.
They released their third mixtape, titled Horizon, on December 20.
2018: Horizon and Stray Kids debut
They released the song "Zone" on September 9 as part of Stray Kids' SKZ-Player series.
|CB97||Leader, Rapper, Vocalist, Producer|
|J.ONE||Vocalist, Rapper, Producer, Maknae|