FIX Gateway Overview - Buildmarkets

Introduction

Buildmarkets’s Client FIX Gateway implements FIX 4.4 protocol specifically for order management. The system delivers institutional-grade, low-latency order routing for partners preferring direct FIX connectivity alongside (or instead of) REST API integration. “FIX 4.4 — only the tags and messages documented in this section are supported.”

FIX vs REST Comparison

Factor	FIX Gateway	REST API
Connection	Persistent TCP session	HTTPS request/response
Latency	Lower (no HTTP overhead)	Standard HTTP
Management	Logon/Logout, heartbeats, sequencing	Bearer JWT + RSA signing
Order types	Equities, single/multi-leg options	Equities, single/multi-leg options
Best use	High-volume institutional flow, OMS/EMS	Partner portals, robo-advisory, mobile
Dollar/fractional	Supported (Market orders only)	Supported
Multileg	Native via MsgType=“AB”	Via `/api/Order/CreateMultiLegOrder`

Setup Requirements

Connectivity requires: Host & Port (assigned during onboarding); SenderCompID (your identifier, Tag 49); TargetCompID (Buildmarkets’s gateway identifier, Tag 56); Heartbeat interval (30 seconds recommended, Tag 108). Contact Buildmarkets support for FIX connectivity setup.

Outbound Messages

Message	MsgType	Purpose
New Order Single	D	Create equity or single-leg option orders
New Order Multileg	AB	Create multi-leg orders (spreads, condors, straddles)
Order Cancel Request	F	Cancel open orders
Order Status Request	H	Request current order status

Inbound Messages

Message	MsgType	Purpose
Execution Report	8	Order acknowledgement, fills, cancellations, rejections
Order Cancel Reject	9	Cancel request rejection
Business Message Reject	j	Application-level message rejection

Quick Start Process

Establish TCP connection to assigned host and port
Send Logon message (MsgType=“A”) with EncryptMethod=0 and HeartBtInt=60
Await gateway Logon acknowledgement
Send orders using MsgType=“D” (single) or MsgType=“AB” (multi-leg)
Process Execution Reports (MsgType=“8”) for fills, updates, and rejections
At session end, send Logout (MsgType=“5”) and await acknowledgement before closing