The Electronic Communications Network (ECN) brokers also pass the orders of their clients to the interbank market but do not necessarily channel them to the liquidity providers. They sometimes transmit orders to other players at the interbank FX market who can take up these offers, such as prime brokers. All ECN brokers are STP (Straight-through processing) brokers, but not all STP brokers are ECN brokers.
Trading on ECN or STP platforms requires a large capital outlay, which raises the barrier for entry. These brokers tend to provide price quotes from several sources, with variable spreads.