Will Cathcart, head of WhatsApp, has accused Telegram of not providing a proper level of security for users, and urged everyone to leave this messenger service created by Pavel Durov. Cathcart wrote about this on his Twitter page.

"Telegram is not end-to-end encrypted by default and offers no e2ee [(end-to-end encryption)] for groups," Cathcart noted.

With this, the head of WhatsApp wanted to show the superiority of WhatsApp over Telegram, which, unlike the American messenger service, does not use end-to-end encryption in regular chats and groups.

Also, Will Cathcart cited a Wired article that claims vulnerability has been found in Telegram that enables even private chats to be read. The article adds that Telegram's privacy policy section still states that user data has never been shared with governments—but this is not the case.

The article notes as well that Telegram has built another API that appears to allow access to user-generated content for mass surveillance purposes.

The Wired columnist states that, in addition to Telegram's lack of secure messaging, this messenger service puts people at risk: during the Russian-Ukrainian war, it was possible to "deceive" Telegram and know the location of each user within a radius of about 3 km.

The head of WhatsApp admitted that his criticism may give the impression that he is pursuing a specific goal with it, but he, nonetheless, did not urge everyone to switch to WhatsApp after leaving Telegram.

“But there are many other great end-to-end encrypted messaging apps people can choose from.  If you aren’t going to use WhatsApp, use one of them – don’t use Telegram” Cathcart concluded.