With any foam-based mattress, you want as much firm support directly applied to the mattress as possible. Therefore, a simple metal frame with thin support beams will not hold up very well, but one with unyielding, thick wooden slats less than 3 inches apart will work fine. If you are considering using a metal frame, we suggest placing a piece of plywood on top of the metal to close up the unsupported surface.
The Metal Frame available on our site is designed to be used with the Casper Foundation and is a great option for a simple setup. If you have any questions about a specific setup, our Customer Experience team is ready to help.