Producer: Dr Luke - Artist: Katy Perry - Producer: Max Martin - Producer: Cirkut - Recording Engineer: Clint Gibbs - Recording Engineer: Peter Carlsson - Recording Engineer: Sam Holland - Recording Engineer: Michael Ilbert - Asst. Recording Engineer: Rachael Findlen - Asst. Recording Engineer: Justin Fox - Asst. Recording Engineer: Elliot Lanam - Mix Engineer: Serban Ghenea - Remixer - Additional Mixer: John Hanes - Mastering Engineer: Chris Gehringer - Programmer: Dr Luke - Programmer: Max Martin - Programmer: Cirkut - Production Coordinator: Irene Richter - Vocals: Katy Perry