RELAY Classic has its own order books, and also pulls orders from the 0x mesh. RELAY Classic utilizes the open order book strategy so these orders are also picked up by other relayers and dapps.

RELAY not only uses RELAY Classic's order books, but also sources liquidity from places such as Curve, Kyber, Uniswap, and Oasis.

For more information on the 0x protocol and 0x mesh, please see