An outbox is the temporary folder in an email client that holds messages after you hit send but before they are actually transmitted. Once a message is delivered to the mail server, it moves out of the outbox.
Outbox vs. Sent Folder
The outbox and the sent folder are easy to confuse. The outbox holds messages that are still on their way out — queued, waiting for a connection, or being processed. The sent folder holds copies of messages that have already left. If a message lingers in the outbox, it usually hasn't been sent yet, often because the device is offline or the server hasn't accepted it.
Why a Message Stays in the Outbox
A message can sit in the outbox when there's no internet connection, the email is too large, the server is busy, or the client is set to send manually. It is closely related to a queued email — a message accepted for sending but waiting its turn. Resolving the connection or attachment issue usually lets the outbox clear and the message move to the sent folder.
Outbox and Topol
Understanding the send pipeline helps you plan reliable campaigns. Design and prepare your emails with Topol, start free at Topol signup, or browse more terms in the Topol glossary.