For API connection Trustless please go to https://docs.ethfinex.com.
The centralised Ethfinex APIs mirror the format from the Bitfinex APIs but using api.ethfinex.com instead of api.bitfinex.com as the base url.
This allows seamless compatibility for any application or website already interacting with the Bitfinex APIs, as well as allow the reuse of any related open source libraries.
Details about the Ethfinex API Documentation can be found here.
For Trustless API
For the Rest API v2
Where endpoint is one of the public endpoints.
For the Websocket API v2