Around 11:00 pm, outrages were reported in India, US, Europe and other parts of the world.
Many users complained that they cannot see when their contacts were last online, while others were unable to adjust their security settings.
As is often the case, many people flocked to Twitter when WhatsApp went down.
Facebook’s WhatsApp messaging service has over 2 billion users worldwide. WhatsApp has 400 million users in India alone, making it one of the most popular messaging platforms in the country.
Earlier this week, Facebook and Instagram went down in several parts of the world as thousands of users complained about being unable to send a post or message. In July last year, Facebook, Instagram and WhatsApp all went down for almost a day.