Although WhatsApp doesn’t go down every day, even they have suffered major outages. One of the most notorious occurred on New Year’s Eve 2015-2016, when users were unable to exchange messages with their friends or family for a few hours.
Interestingly, the service has been down less often in recent years. How do they manage to get their system to handle such a huge load of users at times like Christmas or the New Year?
In October 2016, Facebook purchased WhatsApp for $21.8 billion. From that point on, WhatsApp would move to Facebook’s colossal infrastructure. As a result, WhatsApp has experienced far fewer crashes over the past several years. Not surprisingly, Facebook has even more users than WhatsApp, so they’re prepared to deal with it.
Facebook’s infrastructure is made up of a large number of servers that are spread out across the world. Dozens of them are spread throughout the USA (Georgia, Utah, Alabama, Nebraska, Virginia and more). In Europe, Facebook has data centers in Sweden and Ireland, although it is expected that during 2020 another one will open in Denmark.
They also have infrastructure in Singapore and each of these centers is a real monster in terms of size. One example is Singapore’s 170,000 square meter, 11-levels facility.
In the event that one of the servers fails, Facebook has many additional servers that are initially dedicated to other services, but which could be used for support after just a few minutes of preparation. If those additional servers are still not enough, WhatsApp should have no problem, because Facebook could hire the servers of other large companies, such as Google or Amazon.
And that’s how WhatsApp is able to support millions of simultaneous users across all areas of the globe. The key is a huge and expensive technology infrastructure that few companies in the world can afford.