The largest use of vanillin is as a flavoring, usually in sweet foods.  The ice cream and chocolate industries together comprise 75% of the market for vanillin as a flavoring, with smaller amounts being used in confections and baked goods.
Vanillin is also used in the fragrance industry, in perfumes, and to mask unpleasant odors or tastes in medicines, livestock fodder, and cleaning products. It is also used in the flavor industry, as a very important key note for many different flavors, especially creamy profiles such as cream soda.
Additionally, vanillin can be used as a general-purpose stain for visualizing spots on thin-layer chromatography plates.  This stain yields a range of colors for these different components.
Vanillin–HCl staining can be used to visualize the localisation of tannins in cells.
Vanillin is becoming a popular choice for the development of bio-based plastics.