2. Trading Interface - adharapayments/User-Manual GitHub Wiki

A trading interface is a connection between the ACT platform and a trading venue, which is a market place where liquidity providers quote their bid and ask prices and market participants send their ask and sell orders. A trading interface serves then two basic functions: i) it provides traders with prices in real time, and ii) it accepts and routes trading orders to the market.

Although ACT can support multiple trading interfaces trading on the same or different prime broker accounts, the typical setup accessed through the RESTful API documented here uses only one trading interface.

ACT's trading interfaces quote prices in the form of a full book. This means that a number of liquidity providers are available both to buy and to sell currency pair positions at different prices at every moment in time. Top of Book (ToB) prices are the best available at each moment, i.e. the best bid (available to traders to sell the currency pair) and the best ask (available to buy).

Traders can request not only top of book prices through the RESTful API, but also full book snapshots with a given number of book levels. Book entries specify i) price level and ii) amount available to buy or sell at that level. Therefore, a big order being sent to a trading interface may need a number of book entries to be fulfilled, each with a different price and thus resulting in an average filling price different from the top of book most advantageous price.

In any case, trading venues are responsible for automatically matching the order sent by the trader with the liquidity providers available at each moment in time.