Using hacked clients in RotMG

Is using hacked clients in rotmg detectable or can they be seen from any logs or something like that? And if yes then is there a way to prevent detecting hacks or a ban? I'm asking it because I'm trying to do a self-made client just for fun

No, there is no automatic modified client detection like blizzard's warden or anything. You are free to do anything you want hack wise without fear of ban, that is unless your account is named (unnameds are immune unless a gm sees you in game) and somebody records you and sends it to kabam.