WhatsApp, which claims some 500 million users, said its Web service will be a "mirror" and would require an Internet- connected phone to work. "Our Web client is simply an extension of your phone: the Web browser mirrors conversations and messages from your mobile device - this means all of your messages still live on your phone," WhatsApp said in a blog post.
The new messaging service currently only works with Google's Chrome browser and will not be available to iPhone users "due to Apple platform limitations," according to WhatsApp. Facebook in October completed its buy of WhatsApp in a stock-and-cash deal.
The acquisition highlighted the stunning growth of mobile messaging but also prompted analyst questions on the price paid by Facebook and future plans for the service.