NPC trade is a way to redistribute resources in your village. Any resource can be traded for any other resource. This is a gold feature and 3 golds are needed to do the NPC trade. This is a very handy feature, mainly in the early game.

How to use it? 

There are two ways:

• The NPC trade option can be found in the Marketplace, under the Management tab. When you click the "Exchange resources" button, another window will open. There you can redistribute resouces however you need them. Pressing the button “Distribute remaining resources” will equally redistribute resources.
  
  
  
  
  
• The NPC trade option can be also accessed from any building that permits such trade. When you don't have enough resources for an update, a gold button “Exchange resources” will appear. When you click the button a new window will open with resources distributed according to requirements of the upgrade.

After distribution, you will be moved to your last opened window.

The NPC merchant does not work for you?

The NPC merchant will not work in one of these cases:

• Your account pop is smaller than 40.
• The resource amount you want to exchange is smaller than 50.
• You do not have enough Gold for the exchange.
• You are playing the game through a browser which use a plugin (for example the skype plugin) which is not supported.
• You are playing the game via iPad, or a smart phone which is not supported and therefore the NPC doesn't work.
• Button will not appear in buildings, when there are enough resources for their upgrade.