0x API hosts an Orderbook of 0x Limit Orders that anyone can provide liquidity to or take liquidity from.
Whether you're looking to offer limit orders in your app, or utilize limit orders in MEV searching strategies, the 0x API Orderbook is your go to source.
0x API has an Orderbook on the following chains:
In previous versions of 0x API prior to 0x v4, this functionality was exposed by the "SRA" endpoint.
This section contains the following docs and guides