Combine sugar, water, and salt in a small saucepan and stir to combine.
Bring the mixture to a roaring boil.
Once boiling, lower the heat to medium low and let simmer for 10 minutes.
Remove the mixture from the heat, add in the vanilla extract, and stir to combine.
Use the syrup in any drink right away, or let the syrup cool completely before transferring to an airtight container, and store in the fridge for up to three weeks.