How much weight can I hang on my cabinet doors?
Here’s a typical loading chart based on height of door and number of hinges. See page 3 near the bottom. 

http://downloads.cabinetparts.com/auto/SaliceGeneral.pdf

Notice there are heavy duty hinges too. 

If the shelving is only 3” wide (deep) rather than 10” or so...that’s a clue too.