In a medium saucepan, combine sugar, water, cocoa powder, and salt over medium heat. Stir the mixture occasionally to help dissolve the sugar and cocoa powder completely.

Bring the mixture to a gentle simmer, whisking frequently until all the ingredients have dissolved and the syrup has thickened slightly.

Once the syrup is smooth and the sugar has fully dissolved, remove the pan from heat and add the vanilla extract. Stir until the extract is fully incorporated.

Allow the syrup to cool to room temperature, then transfer it to a clean, airtight container.

Store the syrup in the refrigerator for up to one month for easy access whenever you want to add a chocolatey touch to your meals and drinks.