FIXSIM

FIX Simulator for Faster Testing

Connect your FIX engine and start testing in minutes — no installs, no sales call, no waiting. Test message flow, validate business logic, replay messages, and automate regression scenarios.

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7-day free trial  ·  No credit card required  ·  Up and running in minutes
No installs, browser-based
Manual + automated testing
Session + application layer
REST API + Rule Builder
Built for QA teams, OMS/EMS vendors, broker-dealers, and fintech integration teams.
Why FIXSIM?
1,000+
FIX sessions tested daily
Since 2012
Trusted in production
2M+
FIX messages processed daily
Minutes
From sign-up to connected

FIX Protocol Testing, Simplified

Simulate trading, validate edge cases, high volumes, and develop FIX changes with confidence.

FIXSIM is a web-based platform for testing and validating FIX protocol integrations. Create sessions in minutes, inspect message traffic, and simulate realistic workflows across buy-side and sell-side scenarios.

  • Session layer testing: sequencing, resends, duplicates, recovery
  • Application layer testing: business logic and exception paths
  • Manual control: blotters + message views
  • Automation: Rule Builder + REST API

Best Fit If You Need:

Quickly spin up a test FIX session
Repeatable regression tests
Controlled fills/cancels/rejects/replaces
A reliable always-on test counterparty
CI/scriptable workflows via REST
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Web Based

Create and manage FIX endpoints from your browser. No downloads required.

Automation

Rule Builder + REST API for repeatable scenarios and regression testing.

High Performance

Stress test OMS/EMS behavior with high message volumes and realistic responses.

FIX Versions

Support for FIX 4.0 through FIX 5.0SP2.

Multiuser

Multiple users within your firm can manage their own sessions and workflows.

API Access

Professional and Enterprise plans include developer API access.

FIXSIM Screenshots

FIXSIM blotter view
Blotter Views
Take action on orders and executions with trader-style visibility.
FIXSIM message views
Message Views
Raw FIX and translated tags for faster validation and debugging.
FIXSIM rule builder
Rule Builder
Automate fills/cancels/rejects/replaces for repeatable tests.
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Why FIXSIM?

Web Based

Configure and monitor sessions from any browser. No installs. Fast onboarding.

Always Available

Reliable access for ongoing testing, certification, and regression scenarios.

Simple Pricing

Transparent month-to-month pricing. No annual contracts, no surprise fees. Start free, upgrade when you're ready.

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FAQ

FIXSIM is a web-based FIX simulator for testing FIX protocol integrations. It supports manual workflows (blotters/message views) and automated testing (rules + REST API).
Yes. Many teams use Rule Builder for deterministic behavior and the REST API to drive repeatable test scenarios from scripts or CI.
FIXSIM supports FIX versions 4.0 through FIX 5.0SP2.
FIXSIM is browser-based — nothing to install. Sign up, confirm your email, and you’re immediately placed in a live DEMO account where you can create a FIX session and connect your engine. Most users are sending and receiving FIX messages within minutes of signing up.
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Test and Simulate FIX Order Flow Before Production

99.9% Uptime Web Based Fully Responsive Monthly Subscriptions

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