Which console was Mario Kart World initially prototyped for?

Mario Kart World was initially prototyped for the Nintendo Switch.

Nintendo began prototyping the game in March 2017, shortly before Mario Kart 8 Deluxe was released. The early project was therefore designed around the original Switch rather than the console that ultimately received it.

The concept changed substantially during development. Producer Kosuke Yabuki and the team wanted to move beyond the established circuit-based formula, exploring a connected open world with large races and free-roaming areas.

Development later moved to the Nintendo Switch 2 because the original hardware presented optimization problems for an open-world racing game supporting 24 players. The finished game became a Switch 2 launch title rather than a release for the first Switch.