mkfix

A FIX protocol testing engine for capital markets connectivity, built on mkio and mkui.

Features

• Session Management -- Configure and run FIX sessions as initiator or acceptor. Multiple sessions on the same port with different CompIDs.
• Raw Message Viewer -- Real-time stream of FIX messages in tag=value format with filtering by session, direction, and category.
• Translated Message Viewer -- Human-readable view with field names, enum translations, and expandable detail rows.
• Order Pad -- Send NewOrderSingle, Cancel, and Cancel/Replace requests.
• Order & Trade Blotters -- Live order state machine driven by ExecutionReports; fill and partial fill records.
• Message Replay -- Load production FIX logs and replay them into a test session with speed control, message filtering, and pause/resume.
• IOI & Allocation Viewers -- Indications of Interest and Allocation message tracking.
• Session Protocol -- Logon, Logout, Heartbeat, TestRequest, ResendRequest, SequenceReset, GapFill, PossDupFlag handling, and heartbeat timeout detection.

Installation

pip install mkfix

Or from source:

git clone https://github.com/markuskimius/mkfix.git
cd mkfix
pip install -e .

Usage

mkfix                        # start with defaults (port 8080, mkfix.db)
mkfix -p 9090                # override port
mkfix -d mytest              # use mytest.db
mkfix -d :memory:            # in-memory database
mkfix myconfig.toml          # custom config file

Then open http://localhost:8080 in your browser.

Quick Start

1. Create two sessions in the Session Manager -- one initiator pointing at the other as acceptor on the same port.
2. Start both sessions -- Logon and Heartbeat messages will stream in the Raw Messages pane.
3. Send an order from the Order Pad -- see it in Raw Messages, Translated Messages, and the Order Blotter.
4. Replay a log from Tools > Replay Control -- load a production FIX log and replay it into a test session.

Configuration

mkfix uses a TOML config file (mkfix.toml). The built-in default is used when no config is specified. Key settings:

port = 8080
host = "0.0.0.0"
db_path = "mkfix.db"

Tables, services, and static routes are also configured in the TOML file. See the built-in mkfix.toml for the full schema.

Dependencies

• mkio >= 0.1.36 -- async microservice framework (aiohttp + aiosqlite)
• mkui >= 0.1.10 -- Web Components UI framework

License

GPL-2.0