WhatsApp now has one billion users, which is more than double since Facebook acquired it in late-2014
WhatsApp now has one billion users, which is more than double since Facebook acquired it in late-2014.Facebook/Jan Koum

WhatsApp announced on Monday it has one billion monthly active users, adding 100 million users in just four months. The company's co-founder and CEO Jan Koum revealed that the messaging platform sees 42 billion messages sent and 1.6 billion photos shared each day.

The Facebook-owned smartphone messaging app is inching closer to its parent company, which had 1.59 billion monthly active users as of last month. WhatsApp's user base has surpassed even Facebook Messenger, which reported 800 million users each month on January 27, 2016, and Instagram's 400 million user base.

"We are proud of this milestone, and we're humbled by the extraordinary ways all of you have used WhatsApp," the company said in a blog post on Monday. "Whether it's sharing vital information during natural disasters or health emergencies, finding a date, growing a small business, buying an engagement ring, or seeking a better life — we're honoured to be a small part of what people are doing to make their lives and the lives of those around them better."

According to Koum's post on Facebook, WhatsApp has a total of 1 billion groups around the world, supports 53 languages and exchanges 250 million videos each day. All this is achieved with a small team of 57 engineers, but the company is hiring new talent now.

WhatsApp's user base has more than doubled since Facebook acquired the service for $19 billion in late 2014, according to Facebook CEO Mark Zuckerberg. In a post on Tuesday, Zuckerberg congratulated Koum and Brian Acton, co-founder of WhatsApp, on its impressive feat and the recent changes made on the platform, including dropping the annual subscription fee and new ways to enhance B2C communications, which will create the first revenue opportunity from its massive investment in over a year.

As part of WhatsApp's development for a better service, a recent report indicated the messaging app is getting end-to-end encryption, which ensures device-level security. After adding voice calls, WhatsApp is rumoured to be working on a video-calling feature to rival Skype and other applications.