Yes, forex trading robots do work but under certain conditions only. I avoid buying robots whose seller says they work in every condition.
A genuine forex robot will be built specifically for an instrument (example gold robot), it will also be built for a specific account type such as raw account, specific spread such as ecn spread etc.
But you have to realize than no robot is guaranteed to make profits always, they could also make losses. The reason why people use robots is because it helps them remove emotions from trading.
You can either buy a robot from the online market or you pay someone to build one for you however i prefer buying from the online market so i can read other user reviews about the robot.