Keys go in, keys stay in—unless you press the magical springy bit and grant them freedom. Mount it with command strips or screws and enjoy the thrill of intentional key liberation, no jailbreaks allowed.

This is a spring-loaded key hook that attaches to the wall. The spring latch ensures that your keys cannot pop off the hook or fall out. 

It is designed to accommodate one large command strip. But you could probably get by with a smaller one. Any double sided sticky tape should work. Command strips are just easier to remove, and do not put holes in your walls.

One large command strip is rated to support up to about 4 pounds (1.8 kg). This is more than enough to hold even large keychains. 

Recessed screw holes are included if you prefer to use them. 

It prints in two parts:

• The hook itself - it attaches to the wall using either command strips or screws. 
• The “gate” - the gate attaches to the hook in a way that should be clear from the photos. The gate is designed to flex, so it works like a spring to keep the latch closed. Because of this, I strongly recommend it be printed in PETG, or another filament that can flex and return to it's original shape (which PLA is bad at).

This key hook includes a robust and fully functional spring-loaded latch, based upon n.leinad's Suicide Carabiner. Keep in mind that it is 3D printed plastic. Despite it being pretty sturdy for plastic, it is not strong enough to hold significant amounts of weight. Do not depend upon it for your safety, or rely upon it for anything you hold dear. I adapted n.leinad's model for use with keys. 

These parts are much stronger when printed laying on their side, as oriented in the print profile. I recommend using the print profile. 

Two different build plates are included with the print profile:

• With Supports - I think it is nicer looking if the hook is centered on the hook when it is hanging on the wall. But printing it this way (in the strongest possible orientation) requires supports. Using supports doubles the filament usage from about 10 g to a bit over 19 g. If you don't mind this, the version with supports is the one for you.
• Flat on Build Plate - No Supports - This version doesn't use any supports. It lays flat on the build plate (on it's side). This one is just as strong. But the hook is on one side of the model. This is necessary to print the model in the strongest orientation. Filament usage is about 10 grams. If you don't care as much about aesthetics and care about saving filament, this version is for you. 

The differences between these versions is evident in the photos.