FIX-over-TLS (FIXS) is the standard to secure FIX sessions using the Transport Layer Security (TLS) protocol. The use of FIXS is considered a requirement as it introduces a basic level of security and standard options for interoperability.

Discussion on Cybersecurity  and FIXS can be found in our forums under General Q&A using the tag cybersecurity.

More information on the work from the FIXS Working Group can be found here.

Version 1.0 Draft Standard

Please find below the FIXS Draft Standard documentation.  This comprises of the FIXS specification and a guide for Stunnel users.  The Stunnel guide is intended to allow anyone to get started with FIXS, whilst the FIXS specification is applicable to all TLS implementations.


FIXS Technical Specification - Draft Standard 200.84 KB 779 downloads

Draft Standard - Published January 5, 2018 ...

Please click here to view the FIXS Stunnel User Guide for FIX Applications.

Version 1.0 Release Candidate


FIXS Technical Standard - RC1 252.09 KB 941 downloads

FIX-over-TLS (FIXS) Technical Standard - FIXS is the standard to secure the Transport...