User blog comment:BadFish95/What is the Max Unit and Item Capacity?/@comment-24927152-20150227002522

from what I know, there currently is no "max" for either of the two. the level cap is 500 (I think) keys capacity is 15 (yay) and when expanding unit capacity past 200-300, a message says only that more units causes render lag. If this is the case....

Then there may be no cap.