The worst disruption in WhatsApp's history caused millions of users to flock to rival messaging app Telegram, the firm's founder has revealed.
Pavel Durov, who founded Telegram in 2013, told his followers on the encrypted messaging app about the significant boost to user growth following WhatsApp's difficulties.
The Facebook-owned app experienced around 14 hours of disruption on 13 March, along with the main Facebook app, Facebook Messenger and Instagram.
Compared to the more than 1.5 billion users of WhatsApp, Telegram is a relative minnow in the messaging world with an estimated 200 million users as of March 2018.
During the Facebook apps outage, some users took to Twitter to encourage people to switch over to the lesser-known rival. Figures from Mr Durov suggest millions of people did.
"I see 3 million new users signed up for Telegram within the last 24 hours," he told his followers on Thursday. "Good. We have true privacy and unlimited space for everyone."
It is the worst collective outage in Facebook's history, though the tech giant is still yet to give a reason for the trouble.
"We're aware that some people are currently having trouble accessing the Facebook family of apps," Facebook said in a statement posted on Twitter. "We're working to resolve the issue as soon as possible."
Speculation initially hinted at the possibility of a major DDoS (Distributed Denial of Service) attack, whereby servers are flooded with huge volumes of rogue traffic.
Facebook dismissed this idea, suggesting the outages were the result of a more mundane issue, such as overloaded databases.
While Telegram has never experienced an outage of this scale, attempts have been made in the past to block it in certain regions.
Russia's media watchdog recently attempted to take down Telegram for failing to give up its encryption keys to the security services, however the attempt was unsuccessful.
