"The World Ends with You" was developed by the same team that created the "Kingdom Hearts" series, with input from Jupiter, the company that developed "". The development of the game started two and a half years before its Japanese release, during the development of "Kingdom Hearts II" and the end of development of "Kingdom Hearts: Chain of Memories". At that time, Nintendo had announced the DS, but it was not yet on the market; Square Enix asked the team to make a game specifically for the handheld system.