Yapp began playing pool at age eight. An alumnus of
Saint Patrick's School, he dropped out of school in 2011 to turn professional, although he eventually completed his
GCE Ordinary Level examinations at Coleman College. Reportedly the first professional pool player from Singapore, In 2021, he claimed the Singapore National Snooker Championship, defeating defending champion
Peter Gilchrist 4–2. In the quarter-finals of the 2021
WPA World Ten-ball Championship, Yapp defeated
Jayson Shaw, which moved him up to 8th in the world rankings; he ultimately finished in third place. In the
2021 U.S. Open Pool Championship, Yapp survived a scare against
Wojciech Szewczyk in the third round of the winners bracket by winning 11–10 before scoring upsets in quick succession against defending champion
Joshua Filler 11–4 in the fourth round of the winners bracket and
Shane Van Boening 11–5 in the Last 16. He went on to defeat both
Rodrigo Geronimo and
Dennis Orcollo by a scoreline of 11–6 in the quarterfinals and semifinals respectively, They defeated the European team with a decisive 11–6 final score. Team Europe is made up of Jayson Shaw,
Eklent Kaci,
Francisco Sanchez Ruiz,
David Alcaide, and
Mickey Krause. Yapp was named the first-ever Reyes Cup most valuable player for his outstanding performance throughout the event. A month later, Yapp successfully defended his title by winning back-to-back championships at the International Open Nine-ball in Florida. He defeated
Moritz Neuhausen of Germany, 13–6, and received $40,000 in prize money. In May 2025, Yapp won his first matchroom major open title, defeating Jonas Souto Comino of Spain with a superb 13–1 in the final of the UK Open Pool Championship at Telford International Centre. This significant triumph propelled him from fifth to second place in the matchroom world rankings, trailing
Fedor Gorst at the top. Yapp's victory has also solidified his position in the
Reyes Cup rosters, securing a spot to represent Team Asia this year. In August, Yapp won the inaugural Florida Open beating Shane Van Boening in the finals and a week later he won the prestigious
US Open Nine-ball Championship against defending champion
Fedor Gorst and becoming the first pool player to win three consecutive World Nine-ball Tour (WNT) Open Majors (UK Open, Florida Open, US Open). ==Titles==