# AMM v4 (Constant Product)

AMMv4 is Raydium’s original constant-product automated market maker and the **most widely deployed Raydium contract on Solana**. Often referred to as the **hybrid AMM**, it historically shared idle liquidity with a central limit order book (first Serum, later OpenBook) to improve capital efficiency.

Today, all AMMv4 pools operate purely as **traditional constant-product AMMs**, providing full-range liquidity and fungible LP tokens. AMMv4 remains a battle-tested option for simple liquidity provisioning and long-tail trading pairs.