Place ½ cup of the warm water in a small bowl and add the xanthan gum to it. Whisk quickly and continuously until thickened and well blended.
Add the rest of the water and the sugar substitute to a saucepan over medium heat on the stove. Once hot, whisk in the xanthan gum mixture until completely blended and smooth. Allow the syrup to thicken to your liking.
Remove the syrup mixture from the heat and stir in the maple and vanilla extracts. Let cool and serve or store in an airtight container in the fridge.
Store syrup in a mason jar with a lid or another airtight container. It lasts up to a month when refrigerated.Avoid using granular erythritol based sweeteners as they can give the syrup a gritty texture.Add more water for a thinner consistency.