GoKawiilGmail's 'Undo Send' briefly delays outgoing emails before delivery
Gmail displays a pop-up after sending a message offering 'Undo' and 'View message' options, giving users a short window to stop an email from actually being delivered. The feature works by delaying dispatch rather than retracting an already-sent email, so recipients are never alerted that a message was cancelled. Clicking 'View message' before the countdown ends forfeits the chance to undo.