Every device in an end-to-end encrypted conversation has a special key that’s used to protect the conversation. You can compare keys with someone to check if messages and calls are secured with end-to-end encryption.

When you send a message in an end-to-end encrypted chat, your device locks the message as it's sending. This message can only be unlocked by a device that owns one of the special keys for that chat. The same is true for the content of your video and audio conversations.

No one can read your messages or hear your calls except the people who have these special keys - not even Meta. We couldn't even if we wanted to.

Keep in mind that if you or the receiver of an end-to-end encrypted message or call chooses to share it with someone else outside of the conversation, they’ll be able to see or hear its contents.