What is a Mietbürgschaft? Updated on November 23, 2023 By Nicolas Bouliane The Mietbürgschaft, Bürgschaft, Mietaval or Mietkautionsversicherung is a way to pay your Kaution when you don’t have enough money. Someone else – a parent, a friend or a bank – promises to pay your landlord if there is a problem.1 Sources and footnotes test.de ⤴