A high-performance FIX (Financial Information eXchange) workstation suite for developers, testers, and quants.
One scripting engine, one protocol engine, two user interfaces. Both MXGUI and MXShell are thin front-ends over the same deterministic core, ensuring identical behavior whether you are debugging interactively or running automated CI tests.
mxgui-demo.mp4
| Live Session Monitor | Message Inspector |
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| Dictionary Browser | Script Runner |
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| Message Diff | Offline Toolbox |
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MicroFIX includes first-class Light and Dark themes.
| Dark | Light |
|---|---|
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Unlike QuickFIX or other traditional engines where you must write an entire application layer against an API just to get started, MicroFIX is a complete, out-of-the-box workstation. Connecting, sending, validating, and scripting are all available immediately with zero code required.
Developing FIX applications often means switching between packet captures, text logs, XML dictionaries, and ad-hoc test scripts. MicroFIX brings everything together in a single native application, combining live monitoring, message inspection, scripting, and protocol tooling into one consistent workflow.
- Test FIX Venues: Simulate counterparties and validate raw FIX logs instantly.
- Inspect Deeply: Visual tree views for repeating groups and side-by-side message diffs.
- Automate Reliably: Deterministic scripting with
wait,expect, assertions, and variable injection. - Continuous Logging: Live log streaming that remains uninterrupted even during session reconnects and resets.
- Explore Dictionaries: Browse message and field definitions with one-click message sampling.
- Offline Utilities: Offline toolbox for decoding, validation, comparison, and message generation.
- Native desktop application (no Java, no Electron)
- Interactive CLI with scripting support
- Deterministic scripting
- Offline FIX toolbox
- Interactive FIX dictionary browser
- Custom FIX XML support
- Shared engine between GUI and CLI
- First-class Light and Dark theme support
Download the latest pre-compiled binaries from the Releases page, or install directly via Go:
go install github.com/Infinage/microfix/cmd/mxshell@latest
go install github.com/Infinage/microfix/cmd/mxgui@latest
Desktop GUI (mxgui) (Requires CGO & WebKitGTK on Linux / macOS support via Wails v3):
go build -tags desktop,production -ldflags="-s -w" -o mxgui ./cmd/mxgui
CLI (mxshell):
CGO_ENABLED=0 go build -ldflags="-s -w" -o mxshell ./cmd/mxshell
Get connected and send your first message in 2 minutes.
Both mxshell and mxgui automatically load configuration from:
./.mxrc
~/.mxrc
If neither file exists, MicroFIX starts with sensible defaults. You can modify the configuration via the MXGUI Session Settings page, the MXShell config command, or manually editing the file.
$ mxshell
# Connect to the target defined in config
mxshell> connect
# Send a raw message
mxshell> send 35=A|98=0|108=30|
# Print the logs
mxshell> logs
- Manual Light & Dark Themes: Choose the appearance that suits your preference.
- Live Session Monitor: Zero-lag log streaming via Server-Sent Events capable of handling thousands of messages.
- Interactive Message Diff: Compare FIX messages side-by-side to instantly spot protocol differences.
- Log Search & Navigation: Filter or step through matches with regex search, then jump straight back to a message's original context without losing your place.
mxshell-demo.mp4
- Smart REPL: Command history, arrow-key navigation, and smart auto-completion.
- Headless Automation: Execute batch
.mxsscripts for CI/CD pipelines. - Log Management: Live log streaming, regex searches, and file export.
- Alias support: Reusable FIX templates with macro support
Messages sent from both MXGUI and MXShell support the same expression and macro substitution engine. Inject dynamic values using the $ prefix to access UUIDs, timestamps, session sequence numbers, environment variables, or specific fields extracted directly from incoming messages (e.g., $LASTIN[8,17]).
For a full reference of available macros, aliases, and string slicing capabilities, see the Scripting & Macros section in the FAQs.
Scripts can be executed directly from MXGUI or MXShell using the exact same deterministic engine.
connect
waitstatus Active
set VARS.counter 0
set VARS.max_orders 5
# Execute a batch of orders and verify acknowledgments
while assert $VARS.counter < $VARS.max_orders
# Route order with a dynamically generated ClOrdID
send 35=D|11=$UNIQUE|55=AAPL|54=1|38=100|40=2|
# Wait for the Execution Report (Order ACK)
if wait "35=8 & 39=0"
print Order $VARS.counter acknowledged with ExecID: $BUF[17]
incr VARS.counter
sleep 500
else
print ✗ Order acknowledgment timed out!
disconnect
exit
endif
endwhile
print ✓ Successfully routed $VARS.counter orders.
disconnect
mxgui-script-runner-demo.mp4
Additional sample scripts (acceptor/client test harnesses, order routing examples, etc.) are available in the scripts/ folder.
- Dictionary based validation: MicroFIX supports multiple validation levels (None, Basic, Strict) backed by custom XML dictionaries.
- Automatic Admin Handling: Automatically manages Logon, Logout, Heartbeats, Test Requests, and Sequence Resets.
- Flexible Input: Paste raw
35=D|55=AAPL|...and MicroFIX converts delimiters, computesBodyLength, and calculatesCheckSumon the fly. - Supported Versions: Supports FIX 4.0 through 5.0 SP2 and FIXT 1.1 natively out of the box. See Custom Dictionaries / Vendor Specs in the FAQs for details on loading your own vendor-specific dictionary.
MicroFIX scripts are deterministic and designed to run headless inside CI pipelines. If a wait, expect, or assert command fails, mxshell immediately exits with a non-zero status code, failing your pipeline build.
Example GitHub Actions Workflow:
name: FIX Protocol Regression
on: [push]
jobs:
test-fix-flows:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- name: Install MicroFIX
run: go install github.com/Infinage/microfix/cmd/mxshell@latest
- name: Run Order Flow Test
run: mxshell -f tests/new_order_single.mxs
Common questions on configuration, custom dictionaries, macros/aliases, and troubleshooting are answered in FAQs.
cmd/mxgui Desktop GUI application and script runner
cmd/mxshell Interactive CLI REPL and headless automation
pkg/session Core engine utilizing an actor model to power FIX sessions
pkg/executor Script parsing and evaluation API invoked by both frontends
pkg/ast Abstract Syntax Tree powering flexible `wait`/`expect` expressions
pkg/macros Dynamic variable substitution engine
pkg/message FIX message structures powering the entire suite
pkg/spec XML dictionary parser providing schema data structures
pkg/store In-memory state management (configs, variables)
pkg/broker Pub/sub event broker handling smooth log streaming and reconnects
pkg/ringbuf Efficient circular buffer for CLI log history
pkg/transport Low-level TCP/network API utilized by the session engine
pkg/pretty Console formatting utilities
- Script to import 'aliases' from MiniFIX xml config
- Replay recorded FIX sessions
- Multiple simultaneous sessions
- Performance improvements
Contributions, bug reports, and feature requests are welcome!
If you work with FIX every day and want a faster alternative to heavyweight legacy tooling, give MicroFIX a try. If you are interested in FIX tooling or high-performance Go development, feel free to open an issue or submit a pull request.
MicroFIX is built using Go, Wails, HTMX, and Tailwind CSS.
MIT License