Facebook's WhatsApp said that as of today, it supports more than two billion users around the world.
Facebook Inc, its parent company, said it had about 2.50 billion monthly active users as of Dec. 31.
WhatsApp is the largest messaging platform in the world, though it makes virtually no money and recently set aside plans to introduce ads.
WhatsApp also defended its use of encryption. Every private message sent using WhatsApp is secured with end-to-end encryption by default.
"Strong encryption acts like an unbreakable digital lock that keeps the information you send over WhatsApp secure, helping protect you from hackers and criminals. Messages are only kept on your phone, and no one in between can read your messages or listen to your calls, not even us. Your private conversations stay between you," WhatsApp said.
"Strong encryption is a necessity in modern life. We will not compromise on security because that would make people less safe. 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," the company added.
Facebook is working to encrypt all of its messaging apps, including Messenger and Instagram.