Answer: At almost 14 g of net carbs per serving, mangoes are far too carb-heavy to fit the keto diet.
In the words of 90s Saturday Night Live star, Chris Kattan, "You can't have-a da mango!".
On the keto diet, mangoes are off-limits. A 100 g serving of mango contains 13.4 g of net carbs, a sizeable chunk of any keto dieter's daily carb limit. And a 100 g serving would only account for a small fraction of a mango. Eating an entire mango would cause you to consume 44 g of net carbs, enough to kick most people out of ketosis even in the absence of any other food in your diet. Dried mangoes are even worse, as manufacturers use sugar to preserve the fruit during the dehydration process.
Unfortunately, only a few fruits have a low enough carb count to fit the keto diet. Berries tend to be your best bet. Here are a few keto-friendly options: