The vast majority of online resources that you would be checking out in order to understand what your business card should look like in some way, shape or form would likely only focus on the front of your card at any given point in time. A big part of the reason why that is the case has to do with the fact that it is this side of your card that will be witnessed by whoever receives it at the various events that you attend, but you might still be curious about what the back should have on it.
Most people that are looking for metal cards will likely only want to print something on the front of the card, since suffice it to say that printing on both ends can make the process a bit too costly. That said, there is nothing stopping you from maximizing your card’s value by printing on both of the sides that you have available to you. The reverse of your card is basically free real estate, and the great thing about it is that there really are no standards for what can and can’t be added to it.
Some business card users choose to print their logo on the back of the card because this frees up space on the front for other things such as a more detailed description of their business name as well as a multitude of channels of communication. Logos are important, and printing them on the rear end makes them a lot more prominent without them taking up so much space that you are not left with any room for other more important things.