Does my mattress sit on top of, or inside, my Endy bed frame? Tanner C. 03 May 2021 17:42 Updated Once assembled, your mattress will sit recessed inside your Endy Platform Bed Frame or Upholstered Bed. Related articles Does Endy sell a headboard? What colours do Endy bed frames come in? How do I build the Endy Platform Bed Frame? How do I ship an Endy bed frame back? Do you need tools to assemble or disassemble an Endy bed frame?