>>>>> About QuickFIX
QuickFIX is a full-featured open source FIX engine, currently compatible with the FIX 4.0-4.4 spec. It runs on Windows, Linux, Solaris, FreeBSD and Mac OS X. API's are available for C++, Java, .NET, Python and Ruby.
>>>>> About FIX
The Financial Information eXchange (FIX) Protocol is a "language" which defines specific kinds of electronic messages for communicating securities transactions between two parties. FIX defines only the format of the messages and the session-level interaction between two applications.