WhatsApp billionaire chief executive Jan Koum wrote in a Facebook post Monday, "It's been nearly a decade since (co-founder) Brian (Acton) and I started WhatsApp, and it's been an wonderful journey with some of the best people".
While Koum himself doesn't elaborate on reasoning for the departure, a report from The Washington Post indicates that the decision comes amid growing discord with WhatsApp parent company, Facebook... The company also declined to comment on whether Facebook plans to start advertising on WhatsApp - a business model the founders promised they would never use.
Despite Koum's chummy tone, sources speaking to WaPo claim he's leaving the company due to "clashing" with Facebook.
It's been nearly a decade since Brian and I started WhatsApp, and it's been an incredible journey with some of the best people. "But it is time for me to move on", he said.
He said people were using WhatsApp in more ways than he could have imagined and the team was stronger than ever.
He added: "I'm taking some time off to do things I enjoy outside of technology, such as collecting rare air-cooled Porsches, working on my cars and playing ultimate Frisbee". And I'll still be cheering WhatsApp on - just from the outside.
Koum's defection could put CEO Mark Zuckerberg in an uncomfortable position Tuesday, when he takes the stage at a company conference.
The Facebook founder said he would miss working closely with Mr Koum.
Koum did not reveal when exactly he would depart the company.
Due to end-to-end encryption, information sent through WhatsApp can only be seen by the sender and its recipient.
Zuckerberg is already expected to reiterate some of the apologies he's been offering in the wake of revelations that Facebook allowed Cambridge Analytica, a data mining firm tied to President Donald Trump's 2016 campaign, to obtain personal information from as many as 87 million of its users.
Facebook has taken steps in recent months to generate revenue from WhatsApp, which unlike Facebook's flagship social network does not have advertising. Mr. Koum is up for reelection as a Facebook director, according to Facebook's proxy filing earlier this month. The popular service was developed in 2009 by Koum and Brian Acton, who left Facebook past year and has recently criticized WhatsApp's owner as a reckless abuser of user data. "Those values will always be at the heart of WhatsApp", Zuckerberg wrote in a comment on Koum's Facebook post.