Messaging platform WhatsApp says it has surpassed two billion active users.
The encrypted messaging service, founded in 2009, was bought by Facebook for 19 billion dollars in 2014.
In a blog post announcing the milestone, WhatsApp said it was committed to its encryption model and keeping user messages private.
“Private conversations that once were only possible face-to-face can now take place across great distances through instant chats and video calling,” the firm said.
“There are so many significant and special moments that take place over WhatsApp and we are humbled and honoured to reach this milestone.
“We know that the more we connect, the more we have to protect. As we conduct more of our lives online, protecting our conversations is more important than ever.”
Facebook boss Mark Zuckerberg has previously said the social network’s goal was to become more private and wants to introduce end-to-end encryption to more areas of its family of apps, which also includes Messenger and Instagram.
That stance has been criticised by some – including Home Secretary Priti Patel – who say increased, blanket encryption could prevent criminals, such child abusers and terrorists, from being caught.
But WhatsApp said it believes reducing encryption would be a greater threat to public safety.
“Strong encryption is a necessity in modern life. We will not compromise on security because that would make people less safe,” the company said.
“For even more protection, we work with top security experts, employ industry-leading technology to stop misuse as well as provide controls and ways to report issues — without sacrificing privacy.”