A transparent, heat-sealable coating for transparent PET packaging foils can be provided by using a heat-sealable lacquer based on styrene-containing copolymers, on poly(meth)acrylates, on at least one polyester and optionally on a tackifier, and also the process for the sealing of a foil coated with this lacquer. It is surprising here that, despite the use of a rubber based on styrene-containing polymers that is not optically compatible with polyesters and polymethacrylate, the transparency of the heat-sealable coatings is still very high.