In addition to the range of OnixS FIX Engines for .NET / C#, C++ and Java - OnixS also have a comprehensive library of venue specific FIX venue specific calibrated, tested and certified fast-start reference implementations. These are designed to reduce the integration burden in customizing and supporting the FIX variants for specific venues.

It is a common feature of the FIX Protocol to support customizations of application-level FIX messages. This primarily consists of the ability to add user-defined tags. However in real world use many firms, venues or vendors make significant changes to the FIX messaging specifications. To satisfy these requirements, the OnixS FIX Engine implementations expose the concept of FIX dictionary dialects that are common between the various platform implementations.

The OnixS directConnect venue specific SDKs include a range of FIX integration SDKs. These vary in scope dependent on the specific variant specifications of the the target venues, but generally they include the base OnixS FIX Engine with reference implementation source code samples and a venue specific FIX Dictionary variant dialect that has been implemented, tested and certified by OnixS based on the "FIX Rules of Engagement" specification published by the specific venues.