Yes, you can unsend an email, but how and whether you can do so depends on the email platform you are using. In Gmail, you have an "Undo Send" feature that allows you to recall an email within a short time window after sending—between 5 and 30 seconds, depending on your settings. When you hit send, the email is held in a queue for that period, during which you can click an "Undo" button to stop the message from being sent. To adjust the time period, go to Settings

General > Undo Send, and select a cancellation period up to 30 seconds. After this delay, the email is sent and cannot be unsent.

In Microsoft Outlook, there is a "Recall Email" function that actually sends a request to the recipient's server to delete the email from their inbox if it has not been read yet. However, this only works if both sender and recipient are on the same Exchange Server or Microsoft 365 environment. If the email is already opened by the recipient or if they use a different email system, recall will fail.

Other email platforms like Proton Mail and Apple Mail also use the delayed sending mechanism similar to Gmail, allowing some seconds to unsend an email before it leaves the server. Third-party plugins can add unsend capabilities as well, but all depend on timing and email environments.

In summary, you can unsend an email within a very short timeframe right after sending it in Gmail and similar services via "Undo Send." In Outlook within certain environments, you may recall an unread email. Beyond these conditions or if time has passed, you generally cannot unsend an email, so it is best to double-check your messages before sending.