I currently work on the same thing and there is one problem I don't know how to solve. I have two bots between which I move my items. The info about items and their locations (account name) is stored in database and after trade I want to update item's assetid and location in database. The problem is that I don't know how to map the objects returned by offer.getReceivedItems with old assetid's. I thought about mapping by market_hash_name of old and new items, but I'm not sure it's proper way because some items' prices depend on their visual charecteristics. For example, in CS:GO there can be two items with equal market_hash_name, but with different prices because of the different pattern position. That's why I'm worried about real mapping of the received items with sent items. Do you think there is any way of real mapping?