Go FIX Client for Coinbase Prime

Introduction

This repository contains a lightweight Go-based FIX client that connects to Coinbase Prime's FIX gateway. It provides an interactive REPL to:

• Create new orders
• Look up existing orders (using a local orders.json cache)
• Cancel orders
• View tabular formatted FIX messages

Under the hood, QuickFIX/Go is used to handle FIX message encoding/decoding and session management.

Prerequisites

• Go 1.23+ installed (https://golang.org/dl/)
• A valid Coinbase Prime service account certificate (PEM format) with private key
• A CA certificate bundle (e.g., system-roots.pem) to validate the TLS connection

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1. Configure fix.cfg for Native TLS

Coinbase Prime FIX supports native TLS, so no stunnel or proxy is required.

Quick Setup

Copy the example configuration file and rename it:

cp fix.cfg.example fix.cfg

Then edit fix.cfg to replace placeholder values with your actual credentials:

• Replace YOUR_SVC_ACCOUNT_ID with your service account ID
• Update the SSLCAFile path to point to your system's CA certificate bundle

Generating CA Certificate Bundle

To generate a local CA certificate bundle from your system trust store, run:

security find-certificate -a -p /System/Library/Keychains/SystemRootCertificates.keychain > ~/system-roots.pem

This configuration enables QuickFIX/Go to connect directly over TLS without relying on external proxies like stunnel.

3. API credentials

Your Go FIX client also requires a few environment variables to sign the FIX Logon. Set the following in your shell before running:

export ACCESS_KEY="your_api_access_key"
export SIGNING_KEY="your_api_secret_key"
export PASSPHRASE="your_api_passphrase"
export TARGET_COMP_ID="COIN"
export PORTFOLIO_ID="your_portfolio_id"
export SVC_ACCOUNT_ID="your_service_account_id"

4. Build & Run the Go FIX Client

Run the client:

go run cmd/main.go

On successful FIX Logon, you'll see:

FIX logon SessionID[YOUR_SENDER->COIN]
Commands: new, status, cancel, list, exit

5. REPL Commands

Once the client is running, type one of the following at the FIX> prompt:

Create a New Order

FIX> new <symbol> <MARKET|LIMIT|VWAP> <BUY|SELL> <BASE|QUOTE> <qty> [price] [start_time] [participation_rate] [expire_time]

Quantity Types

• BASE: Quantity specified in base currency (e.g., BTC for BTC-USD)
• QUOTE: Quantity specified in quote currency (e.g., USD for BTC-USD)

Examples

Market Orders:

# Buy 0.1 BTC (base currency)
FIX> new BTC-USD MARKET BUY BASE 0.1

# Buy $1000 worth of BTC (quote currency)
FIX> new BTC-USD MARKET BUY QUOTE 1000

Limit Orders:

# Buy 0.1 BTC at $30000 (base currency)
FIX> new BTC-USD LIMIT BUY BASE 0.1 30000

# Buy $3000 worth of BTC at $30000 (quote currency)
FIX> new BTC-USD LIMIT BUY QUOTE 3000 30000

VWAP/TWAP Orders: You can specify VWAP orders with various combinations of optional parameters:

# Basic VWAP with just price (base currency)
FIX> new BTC-USD VWAP BUY BASE 1.0 50000

# VWAP with start time (quote currency)
FIX> new BTC-USD VWAP BUY QUOTE 50000 50000 2025-08-01T10:00:00Z

# VWAP with start time and participation rate (10%)
FIX> new BTC-USD VWAP BUY BASE 1.0 50000 2025-08-01T10:00:00Z 0.1

# VWAP with all parameters (start, participation rate, and expire time)
FIX> new BTC-USD VWAP BUY BASE 1.0 50000 2025-08-01T10:00:00Z 0.1 2025-08-01T16:00:00Z

VWAP Parameters:

• start_time: When execution should begin (ISO 8601 format)
• participation_rate: Execution aggressiveness (0.0-1.0, e.g., 0.1 = 10%)
• expire_time: When the order should expire (ISO 8601 format)

The order is sent, and the ExecReport (fill/cancel information) will be stored in orders.json.

Look Up an Existing Order

FIX> status <ClOrdId> [OrderId] [Side] [Symbol]

This application automatically generates a unique ClOrdId (Client Order ID) using UnixNano. This value can be collected from orders.json, or from FIX responses sent by the server. OrderId, Side, and Symbol are required, however this app will automatically import these to the request based on the provided ClOrdId.

Example:

FIX> status 1685727281712345678

If orders.json contains that ClOrdId, its OrderId, Side, and Symbol are filled in automatically.

Cancel an order

FIX> cancel <ClOrdID>

This request looks up an order by ClOrdId and attempts to cancel it.

List All Cached Orders

FIX> list

This command lists out all stored orders from orders.json.

Request for Quote (RFQ)

The client supports RFQ (Request for Quote) functionality for obtaining quotes before executing trades:

FIX> rfq <symbol> <BUY|SELL> <BASE|QUOTE> <qty> <price>

Example:

# Request quote to buy $15 worth of SOL-USD with limit price of $250
FIX> rfq SOL-USD BUY QUOTE 15 250

⚠️ Important RFQ Warning

The current implementation automatically accepts any RFQ quote that is received. This is designed for demonstration purposes only. In a production environment, you would want to implement proper quote evaluation logic.

By providing a required limit price, the system sets a worst-case price and helps control the potential risks associated with auto-accepting quotes.

Use caution when testing with real funds, as the system will automatically execute trades upon receiving quotes.

CSV Logging

The client supports logging all FIX messages to a CSV file for analysis and record-keeping:

# Start CSV logging
FIX> csv start

# Stop CSV logging
FIX> csv stop

# Check CSV logging status
FIX> csv

When started, messages are written to a timestamped file (e.g., fix_messages_20250609_143022.csv) in the current directory.

CSV Output Format:

• Direction: OUTGOING or INCOMING
• Timestamp: RFC3339Nano format
• FIX Fields: Common fields in fixed columns (ClOrdID, OrderID, Symbol, Side, OrdStatus, etc.)
• Other Fields: Any additional fields not in predefined columns

This feature is useful for:

• Post-trade analysis and reconciliation
• Debugging message flow
• Audit trails and compliance
• Importing FIX data into spreadsheet applications