> For the complete documentation index, see [llms.txt](https://docs.xpressprotocol.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.xpressprotocol.com/for-developers/api.md).

# API

* Contract API: All trades are executed within contracts on Sonic. To set an order, you call the contract entry point.
* The HTTP API allows you to retrieve information about past and current prices, orders, and trades.
* The WebSocket API is used to receive events about recent changes.

Interaction is available on mainnet with:

* two market contracts [SUSDC](https://sonicscan.org/address/0xc7723fe3df538f76a063eb5e62867960d236accf) and [ETHUSDC](https://sonicscan.org/address/0x75aba7081182a2b1f3b0ead47c074e800805941e)​
* HTTP base endpoint <https://api.xpressprotocol.com>[​](https://api.xpressprotocol.com)
* WebSocket endpoint `wss://sockets.xpressprotocol.com`