Bounce management or bounce handling refers to the processing of returns, also known as non-delivery notification or non-delivery report (NDN or NDR), in email transmission. The aim is to remove unreachable addresses from the mailing lists. A distinction is generally made between soft bounces and hard bounces. Since bounce management falls within the scope of list hygiene, it is the task of the brand to process bounces. However, a professional ESP largely relieves the brand of this work with automatic tools.