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 $32.4 Million SAN RAMON, Calif. - May 2, 2024 - Five9, Inc. (NASDAQ:FIVN), the Intelligent CX Platform provider, today reported results for the first quarter ended March 31, 2024. First Quarter 2024 Financial Results • Revenue for the first quarter of 2024 increased 13% to a record $247.0 million, compared to $218.4 million for the fir ...