Facebook to buy instant messaging service WhatsApp for $19bn

Facebook has agreed to splash out $19billion to acquire over-the-top messaging service WhatsApp.

The deal is the largest the social networking giant has struck in its history, and dwarves the $1 billion the site stumped up for photo-sharing site Instagram in 2012.

It is also much larger than the $1 billion Google was rumoured to have offered for WhatsApp last year.

Facebook founder Mark Zuckerberg confirmed the latest deal in a blog post last night.

He claimed the deal was the result of both firms' commitment to making the world "more open and connected", before going on to reveal what the future holds for WhatsApp.

"WhatsApp will continue to operate independently within Facebook. The product roadmap will remain unchanged and the team is going to stay in Mountain View," wrote Zuckerberg.

"Over the next few years, we're going to work hard to help WhatsApp grow and connect the whole world."

The four-year-old instant messaging service is reportedly used by 450 million mobile users each month, with more than one million people signing up to use it every day.

In the post, Zuckerberg insisted the service will complement Facebook's existing messaging services, rather than replace them.

"Facebook Messenger is widely used for chatting with your Facebook friends, and WhatsApp for communicating with all of your contacts and small groups of people," he explained.

"Since WhatsApp and Messenger serve such different and important users, we will continue investing in both and making them each great products for everyone."

In a separate blog, the WhatsApp team moved to reassure users the service will remain unchanged as a result of the acquisition.

"You can continue to use WhatsApp no matter where in the world you are, or what smartphone you're using. And you can still count on absolutely no ads interrupting your communication," the blog post stated.

"There would have been no partnership between our two companies if we had to compromise on the core principles that will always define our company, our vision and our product."