The golden reference source of the FIX protocol information — specifications, online documentation, community updates, and industry news.
Reference FIX engine implementations in multiple languages.
Should be the first option to consider — has a very simple integration API, and a large market of specialists capable of maintaining the original product or an in-house derivative. Dictionaries, messages, and codecs are generated directly from the FIX repository.
Is not the fastest or best architected implementation of FIX in the industry, but is so straightfoward, that maintenance and minor adjustments should not be a problem even for an amateur software engineer.
Performance bottlenecks are well known and can be addressed in-house without full rewrite — excessive dynamic memory allocation, suboptimal codecs, message representation, and data containers.
An interactive web-based FIX traffic analyzer. Has enterprise-friendly commercial offering.