The posting receipt is the confirmation of the postal service (e.g. Deutsche Post AG) for the sender of a mail piece that (and when) the sender has submitted the mail piece to the postal service. The posting receipt contains (for mailings within Germany) e.g. the date of admission and a tracking number for the electronic delivery tracking. A posting receipt is the unequivocal evidence that (or when) a mail piece was sent. The posting receipt is often used in combination with registered items and in online trading. On the one hand, the dealer can prove that the goods were sent, on the other hand, the customer can, if required, prove that the goods were returned.