There are two types of integration to choose from: an ECN straight-through processing (STP) integration and a market maker integration. The STP model allows for direct execution of an order, allowing the trader’s order to go directly through and be filled. The orders are routed directly to a liquidity provider, who is one of the A book brokers, and filled. Because the broker is direct... https://www.openforexbroker.org/a-book-or-b-book-broker/