Resources

FIX Trading Community — fixtrading.org

The official body that maintains the FIX Protocol standard. Primary source for all FIX specifications.

FIX Protocol Specification — fixtrading.org/standards

Full technical specifications for FIX 4.0 through FIX 5.0 SP2 and FIXT 1.1.

NYSE Pillar Gateway FIX Specification — nyse.com/connectivity/documents

Official FIX specification for connecting to NYSE Pillar trading platforms.

NASDAQ FIX Connectivity — nasdaqtrader.com/Trader.aspx?id=FIX

NASDAQ's FIX connectivity documentation and technical specifications.

Cboe U.S. Equities FIX Specification — cboe.com/us/equities/support/technical/

Technical specifications for Cboe's U.S. equities markets, including BZX, BYX, EDGX, and EDGA.

IEX FIX Specification — iex.io/documents/iex-fix-specification

IEX Exchange FIX order entry specification for equity trading.

Cboe Options FIX Specification — cdn.cboe.com/resources/membership/…

Covers all four Cboe options venues: Cboe Options (XCBO), C2 (C2OX), BZX Options (BATO), and EDGX Options (EDGO). Includes SPX, VIX, and equity options order entry.

Nasdaq Options Technical Specifications — nasdaqtrader.com/trader.aspx?id=OptnsTechSpecs

Covers all five Nasdaq options venues: PHLX (XPHL), ISE (XISX), GEMX (GMNI), MRX (MCRY), and Nasdaq BX Options (XBXO).

MIAX Options FIX Specification — miaxoptions.com/specifications

Covers MIAX (MIAX), MIAX Pearl (MPRL), and MIAX Emerald (EMLD). Three distinct fee models on shared MIAX technology.

BOX Options FIX Specification — boxoptions.com/technology

BOX Options Exchange (BOX) FIX specification including the Price Improvement Period (PIP) auction mechanism.

NYSE Options FIX Specification — nyse.com/connectivity/documents

Covers NYSE American Options (XASE) and NYSE Arca Options (ARCO). Separate from NYSE Pillar equities connectivity.

MEMX Options Specification — memxtrading.com

Launched 2023. Verify the current spec before implementing — fee schedules and technical parameters are subject to change. Source checked June 2026.

ISO 10383 Market Identifier Codes (MIC) — iso20022.org/market-identifier-codes

Updated quarterly. Used in FIX Tag 207 (SecurityExchange) to identify trading venues.

ISO 4217 Currency Codes — six-group.com

Used in FIX Tag 15 (Currency) and Tag 120 (SettlCurrency) for settlement currency identification.

ISO 3166 Country Codes — iso.org

Used in FIX Tag 470 (CountryOfIssue) and other country-identifying fields.

SEC EDGAR — sec.gov/edgar

Public filings including exchange rule changes and FIX-related regulatory notices.

FINRA Rules — finra.org/rules-guidance

Regulatory guidance relevant to FIX reporting and trade reporting facilities.

FIX Protocol LinkedIn Group — linkedin.com

Active community of FIX practitioners — vendors, sell-side, buy-side, and exchange technologists.

Stack Overflow FIX tag — stackoverflow.com/questions/tagged/fix-protocol

Q&A for FIX Protocol implementation questions, session troubleshooting, and message parsing.