1. A server system in an electronic trading system to facilitate an exchange of messages with a remote client application, the server system including: a plurality of application servers hosting a plurality of business applications; and a plurality of application program interface servers hosting a plurality of Application Program Interfaces (APIs) to provide programmatic access to the plurality of business applications, each of the APIs are configured to receive request messages compiled from the remote client application, the first and second request messages, respectively target first and second APIs of the plurality of APIs, each API comprises at least one common data component, and the first request message includes a first payload specific for the first targeted API and the second request message includes a second payload specific for the second targeted API, the first payload and the second payload each comprise a reusable identified schema definition specific to the API that is targeted.