The sport's Australian top body, Snow Australia, said it was "shocked and saddened" by Pullin's death.
"Alex was a beloved member of the Snow Australia community and he will be dearly missed," it said in a statement.
"An incredible athlete, beloved teammate and role model, you will be sorely missed," the Australian Olympic Team, which Pullin had been part of three times, said.
The chief executive of the Olympic Winter Institute of Australia, Geoff Lipshut, described the athlete as "one of our great winter sports pioneers". He told Reuters news agency that Pullin had retired from snowboarding last month but had not announced the decision before his death.
Other athletes and commentators have also paid tribute, with many describing him as a kind and generous person.
"The world will miss such a talented human and a double world champion without ego and without selfishness who is everyone's best mate," wrote former Australian speed skater Steven Bradbury.
Pullin, who grew up in the town of Mansfield, Victoria, first learned to snowboard when he was eight years old, going on to win world championship titles in 2011 and 2013.
He also represented Australia in snowboard cross at the 2010, 2014 and 2018 Olympics