In a small pot set on medium-high heat, mix water and sugar until dissolved. Bring to a simmer. Reduce heat to low and simmer for 3 minutes, stirring regularly.
1¼ cup water, 1½ cup Sugar
Stir in cocoa powder and salt, and continue stirring and simmering. Continue simmering for about two more minutes or until cocoa powder is all dissolved and the mixture is smooth and thickened. Remove from heat and stir in vanilla. Store chocolate syrup in a jar in the refrigerator.