WhatsApp is one of the largest mobile instant messaging services as they are now processing over 50 billion messages per day. This figure indicates that WhatsApp may have overtaken the total number of SMS messages sent per day.
WhatsApp CEO Jan Koum confirmed the figure on stage at the DLD conference in Germany. The 50 billion number is nearly double from the 27 billion messages that were sent out per day in June 2013.
WhatsApp used to be a free service, but the company started charging $0.99 per year to help cover infrastructure costs.