Does Vanish Mode Work on Both Ends?

Both you and the recipient will exit Vanish mode, but you'll still be able to see the messages you sent in Vanish mode until you close the window. After that, they'll be gone forever.

Does vanish mode delete messages on both sides?

Vanish mode is activated for both sides i.e., sender and receiver of the message. They will see a different screen with Vanish mode written promptly on the chat. So yes, the other person will come to know about the Vanish mode.

Can you tell if someone is using Vanish mode on Messenger?

If you or your friend take a screenshot of the Vanish Mode chat, both users will be alerted. ... It's also turned off by default, meaning that if someone sends you a Vanish Mode message, you'll have to put your own chat in Vanish Mode before you see their messages (and vice-versa).