Exhibit 99.1 Five9 Reports First Quarter 2024 Results 13% Year-Over-Year Growth in Total Revenue 20% Year-Over-Year Growth in Subscription Revenue GAAP Operating Cash Flow of 32.4MillionSANRAMON,Calif.−May2,2024−Five9,Inc.(NASDAQ:FIVN),theIntelligentCXPlatformprovider,todayreportedresultsforthefirstquarterendedMarch31,2024.FirstQuarter2024FinancialResults•Revenueforthefirstquarterof2024increased13247.0 million, compared to $218.4 million for the fir ...