> ## Documentation Index
> Fetch the complete documentation index at: https://developer.buildmarkets.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# FIX Gateway Overview

> Buildmarkets's Client FIX Gateway implements FIX 4.4 for institutional-grade, low-latency order management and routing.

## 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

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