Technically Keto is no carbs (< 50gms), but there is modified keto and/or low carb diets where some carbs are tolerable.
Keto is generally practiced by those who need to lose a great deal of weight, e.g. overweight or obese, and want to jump-start their weight loss. I hover around 12% and practice low or no carbs 1-2 times/week.