Coordinator [Production] – Irene Richter, Megan Dennis, Vanessa SilbermanDrums, Keyboards, Producer, Programmed By – Benny Blanco , Dr. Luke, Max MartinEngineer – Emily Wright, Sam HollandEngineer [Assistant] – Tatiana Gottwald, Tucker BodineEngineer [Mix, Assistant] – Tim RobertsEngineer [Mix] – John HanesMixed By – Serban GheneaProducer – Benny Blanco Written-By – Benjamin Levin, Bonnie McKee, Katy Perry, Lukasz Gottwald, Max Martin

Coordinator [Production] – Irene Richter, Megan Dennis, Vanessa SilbermanDrums, Keyboards, Producer, Programmed By – Dr. Luke, Max MartinEngineer – Emily Wright, Sam HollandEngineer [Assistant] – Tatiana Gottwald, Tucker BodineEngineer [Mix, Assistant] – Tim RobertsEngineer [Mix] – John HanesMixed By – Serban GheneaSaxophone – Lenny PickettWritten-By – Bonnie McKee, Katy Perry, Lukasz Gottwald, Max Martin

Coordinator [Snoop Dogg's Production] – Ted ChungDrums, Keyboards, Producer, Programmed By – Benny Blanco , Dr. Luke, Max MartinEngineer – Emily Wright, Sam HollandEngineer [Assistant] – Aniela Gottwald*Engineer [Mix, Assistant] – Tim RobertsEngineer [Mix] – John HanesFeaturing, Vocals – Snoop DoggMixed By – Serban GheneaPerformer [Bieberaphone] – Tamra NatisinProducer – Benny Blanco Written-By – Benjamin Levin, Bonnie McKee, Calvin Broadus, Katy Perry, Lukasz Gottwald, Max Martin

Engineer [Additional] – Carlos Oyanedel, Damien LewisEngineer [Assistant] – Josh HoughkirkInstruments [All] – Mikkel S. Eriksen, Sandy Vee, Tor Erik HermansenManagement [Stargate] – Danny D*, Tim Blacksmith Mixed By – Phil Tan, Sandy VeeProducer – Sandy Vee, Stargate Recorded By – Mikkel S. Eriksen, Miles WalkerWritten-By – Ester Dean, Katy Perry, Mikkel S. Eriksen, Sandy Wilhelm, Tor Erik Hermansen

Engineer [Mix, Assistant] – Tim RobertsEngineer [Mix] – John HanesInstruments [All] – Mikkel S. Eriksen, Tor Erik HermansenManagement [Stargate] – Danny D*, Tim Blacksmith Mixed By – Serban GheneaProducer – Stargate Recorded By – Ester Dean, Miles WalkerWritten-By – Ester Dean, Katy Perry, Mikkel S. Eriksen, Tor Erik Hermansen

Bass – Daniel SilvestriDrum Programming – C. "Tricky" Stewart*, Pat ThrallDrums [Live] – Josh FreeseEffects [Special Tweaking And Electronic Breaks] – Chris "Tek" O'Ryan, C. "Tricky" Stewart*, Mike Green Engineer – Andrew Wuepper, Brian "B-Luv" Thomas, Chris "Tek" O'RyanEngineer [Additional] – Pat ThrallEngineer [Assistant] – Charles Malone, Justin Roberts , Kory Aaron, Luis Navarro , Mark Gray , Nicolas Essig, Randy Urbanski, Steven Dennis, Travis HarringtonEngineer [Guitars And Bass], Recorded By [Guitars And Bass], Sounds [Guitar], Tracking By [Guitar] – Nick ChahwalaEngineer [Live Drums] – Steve ChurchyardGuitar – Charles Malone, Daniel Silvestri, Julio MirandaMixed By – Jaycen-Joshua*Mixed By [Assistant] – Giancarlo LinoProducer – C. "Tricky" Stewart*Producer [Vocals] – Kuk HarrellSounds [Vocal] – Andrew WuepperWritten-By – Christopher Stewart, Katy Perry, Monte Neuble

Arranged By, Conductor – L. Leon Pendarvis*Coordinator [Production] – Irene Richter, Megan Dennis, Vanessa SilbermanDrums, Keyboards, Producer, Programmed By – Dr. Luke, Max MartinEngineer – Emily Wright, Sam HollandEngineer [Assistant] – Tatiana GottwaldEngineer [Mix, Assistant] – Tim RobertsEngineer [Mix] – John HanesMixed By – Serban GheneaWritten-By – Katy Perry, Lukasz Gottwald, Max Martin

Coordinator [Production] – Irene Richter, Megan Dennis, Vanessa SilbermanDrums, Keyboards, Producer, Programmed By – Ammo , Dr. Luke, Max MartinEngineer – Emily Wright, Sam HollandEngineer [Assistant] – Aniela Gottwald*Engineer [Mix, Assistant] – Tim RobertsEngineer [Mix] – John HanesMixed By – Serban GheneaWritten-By – Joshua Coleman, Katy Perry, Lukasz Gottwald, Max Martin

Drum Programming – Brian "B-Luv" Thomas, C. "Tricky" Stewart*Engineer – Andrew Wuepper, Brian "B-Luv" ThomasEngineer [Additional] – Pat ThrallEngineer [Assistant] – Jason Sherwood, Luis Navarro , Mark Gray , Randy Urbanski, Steven DennisGuitar – Brent Paschke, Michael ThompsonKeyboards – C. "Tricky" Stewart*, Monte NeubleMixed By – Jaycen-Joshua*Mixed By [Assistant] – Giancarlo LinoProducer – C. "Tricky" Stewart*Producer [Vocals] – Kuk HarrellRecorded By [Guitars] – Andrew Wuepper, Chris "Tek" O'RyanSounds [Vocal] – Andrew WuepperWritten-By – Brian Thomas*, Christopher Stewart, Katy Perry, Monte Neuble

Drums, Piano, Producer – Greg WellsEngineer [Mix, Assistant] – Tim RobertsEngineer [Mix] – John HanesMixed By – Serban GheneaProgrammed By, Synth – Fabien Waltmann, Greg WellsRecorded By – Lewis TozourWritten-By – Christopher Stewart, Greg Wells, Katy Perry

Bass – Michael ThompsonDrum Programming – C. "Tricky" Stewart*, Pat ThrallDrums [Live] – Josh FreeseEngineer [Additional] – Pat ThrallEngineer [Assistant] – Luis Navarro , Nicolas Essig, Randy Urbanski, Steven DennisEngineer [Live Drums] – Steve ChurchyardEngineer [Mix, Assistant] – Tim RobertsEngineer [Mix] – John HanesEngineer, Recorded By [Guitars] – Andrew Wuepper, Brian "B-Luv" Thomas, Chris "Tek" O'RyanGuitar – Brent Paschke, Michael ThompsonKeyboards – C. "Tricky" Stewart*, Monte NeubleMixed By – Serban GheneaProducer – C. "Tricky" Stewart*Producer [Vocals] – Kuk HarrellSounds [Vocal] – Andrew WuepperWritten-By – Christopher Stewart, Katy Perry, Monte Neuble, Stacy Barthe

Drums, Piano, Producer, Programmed By – Greg WellsEngineer [Mix, Assistant] – Tim RobertsEngineer [Mix] – John HanesMixed By – Serban GheneaRecorded By – Lewis TozourWritten-By – Greg Wells, Katy Perry

Celesta, Percussion [Additional] – Adam MarcelloEdited By – Eric CaudieuxGuitar – Katy PerryInstruments [All Other], Producer – Jon BrionMastered By – Patricia SullivanMixed By [Assistant], Recorded By [Assistant] – Chandler Harrod, Jake GorskiMixed By, Recorded By – Greg KollerWritten-By – Katy Perry, Lukasz Gottwald, Max Martin

Coordinator [Production] – Irene Richter, Katie Mitzell, Megan Dennis, Vanessa SilbermanDrums, Keyboards, Producer, Programmed By – Cirkut*, Dr. Luke, Max MartinEngineer – Emily Wright, Sam HollandEngineer [Assistant] – Aniela Gottwald*, Clint Gibbs, Tucker BodineEngineer [Mix, Assistant] – Phil Seaford, Tim RobertsEngineer [Mix] – John HanesMixed By – Serban GheneaWritten-By – Bonnie McKee, Katy Perry, Lukasz Gottwald, Max Martin

Coordinator [Production] – Irene Richter, Katie MitzellEngineer – Clint GibbsEngineer [Assistant] – Angelo CaputoEngineer [Mix, Assistant] – Phil Seaford, Tim RobertsEngineer [Mix] – John HanesInstruments [All], Producer, Programmed By – Cirkut*, Dr. LukeMixed By – Serban GheneaWritten-By – Bonnie McKee, Henry Walter, Katy Perry, Lukasz Gottwald, Max Martin

Bass – Daniel SilvestriDrum Programming, Sequenced By – C. "Tricky" Stewart*, Kenneth "Soundz" Coby*Effects [Vocal FX], Rhythm Guitar, Vocoder – Pat ThrallEngineer – Andrew Wuepper, Brian "B-Luv" Thomas, Chris "Tek" O'Ryan, Pat ThrallEngineer [Assistant] – Charles Malone, James Hunt , Justin Roberts , Kory Aaron, Luis Navarro , Mark Gray , Randy Urbanski, Stephen Villa, Steven DennisEngineer [Guitars And Bass], Recorded By [Guitars And Bass] – Nick ChahwalaEngineer [Mix, Assistant] – Phil SeafordEngineer [Mix] – John HanesGuitar – Charles Malone, Daniel Silvestri, Julio MirandaKeyboards – C. "Tricky" Stewart*, Monte NeubleMixed By – Serban GheneaProducer – C. "Tricky" Stewart*Producer [Vocals] – Kuk HarrellProgrammed By [Additional] – Mike Green Written-By – Christopher Stewart, Katy Perry, Matt Thiessen*, Monte Neuble

Coordinator [Production] – Irene Richter, Megan Dennis, Vanessa SilbermanDrums, Keyboards, Producer, Programmed By – Ammo , Dr. Luke, Max MartinEngineer – Emily Wright, Sam HollandEngineer [Assistant] – Aniela Gottwald*Engineer [Mix, Assistant] – Tim RobertsEngineer [Mix] – John HanesFeaturing, Vocals – Kanye WestMastered By – Chris GehringerMixed By – Serban GheneaRecorded By [Additional Vocals] – Noah GoldsteinWritten-By – Joshua Coleman, Katy Perry, Lukasz Gottwald, Max Martin

Coordinator [Production] – Irene Richter, Katie MitzellDrums, Keyboards, Programmed By – Cirkut*, Dr. Luke, Max MartinEngineer – Emily Wright, Sam HollandEngineer [Assistant] – Clint Gibbs, Tatiana Gottwald, Tucker BodineEngineer [Mix, Assistant] – Phil SeafordEngineer [Mix] – John HanesFeaturing, Vocals – Missy ElliottMixed By – Serban GheneaProducer [Original] – Dr. Luke, Max MartinProducer [Remix] – Cirkut*, Dr. LukeRecorded By [Additional Vocals, Assistant] – Ed Lidow*Recorded By [Additional Vocals] – Julian VasquezSaxophone – Lenny PickettWritten-By – Bonnie McKee, Katy Perry, Lukasz Gottwald, Max Martin

Arranged By [Remix], Producer [Remix], Remix [Mash-Up] – Tommie SunshineEngineer – Mark VerbosWritten-By – Benjamin Levin, Bonnie McKee, Calvin Broadus, Ester Dean, Joshua Coleman, Katy Perry, Lukasz Gottwald, Max Martin, Mikkel S. Eriksen, Sandy Wilhelm, Tor Erik Hermansen