Freight broker
The middleman who matches a shipper's freight with a carrier to haul it, and who usually pays you for the load.
A freight broker is the middleman between the company that has freight and the carrier that hauls it. The shipper hires the broker to find a truck, the broker posts the load or calls carriers, and you book it. The broker is usually who sends the rate confirmation and who pays your invoice.
Brokers make their money on the spread: the shipper pays them one number, they pay you a lower one, and the difference is their cut. That is normal. What matters to you is whether the rate works for your truck and whether the broker pays on time and pays what was agreed.
Before you haul for a new broker, it is worth checking their credit and payment history, because a good rate is worthless if the invoice never gets paid. Once you deliver, you invoice the broker against the rate con and the signed BOL.
Related: rate confirmation, bill of lading, factoring.