1 unstable release

0.3.0	Sep 24, 2025

#571 in Finance

Used in 2 crates

MIT license

1.5MB
1.5K SLoC

miniFIX

A bare essentials library for Financial Information Exchange (FIX)

What is miniFIX • Features • How To Use • Documentation • License

📌 Table of Contents

Table of Contents

What is miniFIX
Features
How to Use
Documentation
License

🤔 What is miniFIX

minifix is a high-performance, memory-safe Rust library for parsing, manipulating, and generating FIX (Financial Information Exchange) protocol messages. Designed for speed, safety, and ease of use in financial trading systems, it provides zero-copy parsing, type-safe field access, and comprehensive support for FIX protocol versions 4.0 through 4.4. miniFIX is a derivation of the FerrumFIX crate. Our goal is to create a slimmed-down-bare-essentials version of the original crate.

Please note that a lot of the code in miniFIX is drawn from FerrumFIX, and published in accordance with the MIT license (see LICENSE).

Use Cases

Trading Systems: Parse and generate order messages, execution reports, and market data
Market Data Processing: Handle real-time market data feeds with minimal latency
FIX Gateway Development: Build protocol bridges and message routing systems
Financial Analytics: Process historical trade data and market information
Risk Management: Monitor and analyze trading activity in real-time

Architecture

miniFIX is organized into several focused crates:

minifix: Main library with parsing, encoding, and field type handling
minifix-dictionary: FIX protocol specifications and field definitions
minifix-codegen: Code generation for FIX message structures
minisofh: Simple Open Framing Header (SOFH) support

📷 Features

Core Parsing

Zero-copy parsing - Process messages without unnecessary allocations
Type safety - Compile-time guarantees for field types and message structure
High performance - Optimized for low-latency trading applications
Memory safety - No buffer overflows or undefined behavior

FIX Protocol Support

Multiple FIX versions - Support for FIX 4.0, 4.1, 4.2, 4.3, and 4.4
Message validation - Comprehensive message structure and field validation
Repeating groups - Full support for FIX repeating group structures
Field type handling - Type-safe field value handling with validation

Integration & Performance

Async support - Built-in Tokio integration for async applications
Session management - Session handling and heartbeat management
JSON encoding - JSON representation of FIX messages
SIMD optimizations - Vectorized operations where possible

Example Usage

use minifix::prelude::*;

// Parse a FIX message
let message = b"8=FIX.4.2|9=49|35=D|49=SENDER|56=TARGET|34=1|52=20230101-12:00:00|55=AAPL|54=1|38=100|10=123|";
let mut decoder = Decoder::new(Dictionary::fix42());
decoder.config_mut().separator = b'|'; // For display (normally SOH)

let msg = decoder.decode(message)?;
println!("Symbol: {:?}", msg.get::<&[u8]>(fix42::SYMBOL)?); // "AAPL"

// Type-safe field access
let seq_num: u32 = msg.get(fix42::MSG_SEQ_NUM)?;           // Integer field
let symbol: &[u8] = msg.get(fix42::SYMBOL)?;               // String field  
let side: fix42::Side = msg.get(fix42::SIDE)?;             // Enumeration field

// Encode a new message
let mut encoder = Encoder::new();
let mut buffer = Vec::new();
let mut new_msg = encoder.start_message(b"FIX.4.3", &mut buffer, b"D");

new_msg.set(fix43::CL_ORD_ID, "ORDER-12345");
new_msg.set(fix43::SYMBOL, "AAPL");
new_msg.set(fix43::SIDE, fix43::Side::Buy);
new_msg.set(fix43::ORDER_QTY, 100);

let (encoded, _) = new_msg.done();
println!("Encoded: {}", String::from_utf8_lossy(encoded));

🚙 How to Use

Installation

Add to your Cargo.toml:

[dependencies]
minifix = "0.1"

Or install with cargo:

cargo add minifix

Optional Features

Enable optional features as needed:

minifix = { version = "0.1", features = [
    "fix44",          # FIX 4.4 support (includes 4.0-4.3)
    "utils-chrono",   # chrono integration for date/time fields
    "utils-tokio",    # async/Tokio support
    "json-encoding"   # JSON encoding support
]}

Example

use minifix::prelude::*;
use minifix::tagvalue::{Decoder, Encoder};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Parse a FIX message
    let message = b"8=FIX.4.2|9=73|35=D|49=SENDER|56=TARGET|34=1|52=20230101-12:00:00|11=ORDER1|55=AAPL|54=1|38=100|40=2|44=150.50|59=0|10=123|";
    
    let mut decoder = Decoder::new(Dictionary::fix42());
    decoder.config_mut().separator = b'|';
    
    let msg = decoder.decode(message)?;
    
    // Access fields with type safety
    println!("Order ID: {:?}", msg.get::<&[u8]>(fix42::CL_ORD_ID)?);
    println!("Symbol: {:?}", msg.get::<&[u8]>(fix42::SYMBOL)?);  
    println!("Side: {:?}", msg.get::<fix42::Side>(fix42::SIDE)?);
    
    // Encode a new message
    let mut encoder = Encoder::new();
    let mut buffer = Vec::new();
    let mut new_msg = encoder.start_message(b"FIX.4.2", &mut buffer, b"8");
    
    new_msg.set(fix42::ORDER_ID, "EXEC-001");
    new_msg.set(fix42::SYMBOL, "AAPL");
    new_msg.set(fix42::SIDE, fix42::Side::Buy);
    
    let (encoded, _) = new_msg.done();
    println!("Encoded: {}", String::from_utf8_lossy(encoded));
    
    Ok(())
}

📚 Documentation

Comprehensive documentation is available at docs.rs/minifix, including:

API reference for all public types and functions
Tutorial on FIX message parsing and encoding
Examples of different message patterns and use cases
Best practices for financial application development

🖊 Author

CryptoPatrick

Keybase Verification:
https://keybase.io/cryptopatrick/sigs/8epNh5h2FtIX1UNNmf8YQ-k33M8J-Md4LnAN

minifix-dictionary