Ruled me has a great article on this
I will say that during my first 30 days of the ketogenic diet, I cut all sweetners, including the artificial stuff. I went cold turkey to battle my sweet tooth. The cravings went away after about 2 weeks of going cold turkey. I felt the best when my body adapted to keto with no artificial sugars, no diet soda, and no caffeine.
However, once I was in the maintenance phase of my journey (after day 91 + ) I slowly introduced artificial sugars so that I could enjoy coffee and tea on a daily basis. I opened up to more recipes that require sweetness, such as fat bombs, I began to explore the different varieties of sweeteners such as stevia, sweetleaf, erythrotol. I also explored other sugar free products such as sauces and flavorings. Ketogenic purists gasp at the mention of using any artificial sweetners so for this reason, I consider the second 90 days of my journey to be more Low Carb High Fat (LCHF) than ketogenic. I simply had artificial sweeteners because it allowed me to enjoy daily staple foods like coffee and fat bombs, and because quite frankly, my weight didn’t stall and I had no negative health effects (headaches, tummy troubles, bloating) after using sugar free sweeteners. For me, having a small daily treat makes this way of eating easy and pleasant to follow.