Seconding this... it'll just barely run on the Zero W, but you need 64-bit Java to remotely access your controller through unifi.ubnt.com, and there'll be long

Seconding this... it'll just barely run on the Zero W, but you need 64-bit Java to remotely access your controller through unifi.ubnt.com, and there'll be long delays whenever the database needs any maintenance. (I set up a Zero with the Unifi Controller -- connecting to the LAN using a Chromecast Ethernet Adaptor -- about a year ago, and had this problem, so I switched to a 3B, and all is well now.)