FIXSIM
Test and Validate FIX Integrations Faster
Simulate FIX sessions, validate business logic, and automate repeatable testing scenarios. A SaaS based solution built for developers, QA teams, and trading integrations specialists.
- Session + application layer
- Trade blotters
- Reatime traffic view
- Control fills/cancels/rejects
- Rule Builder automation
- REST API for scripts / CI
- No installs, month-to-month
On-demand FIX testing — manual or automated.
Who This Is For
OMS / EMS Developers
Test integrations faster by simulating broker/exchange behavior and controlling responses.
QA & Test Engineers
Build repeatable regression tests, simulate edge cases, and validate outcomes without waiting on counterparties.
Trading Integrations Specialists
Validate session reliability, message compliance, and business logic before production releases.
Common FIX Testing Problems We Solve
See FIXSIM in Action
Add real product screenshots here. These “proof” visuals usually increase conversions more than any copy change.
Blotter Views
Message Views
Rule Builder
FIX Testing Categories
Session Layer Testing
The most common use of the FIX protocol is over a TCP/IP socket. At the start of a FIX session, the initiator opens a socket to the acceptor. Once connected, the first message is a Logon.
If the Logon is validated and accepted, the acceptor replies with a Logon confirming the session. If rejected, the socket is terminated.
Session-layer testing includes dropped messages, unexpected sequencing, resend requests, and duplicates. FIXSIM provides the ability to send invalid messages, send resend requests, and process resend requests from your FIX-enabled application.
Application Layer Testing
The session layer ensures delivery and message order. The application layer validates business logic. For example, if an order is submitted for buying 500 shares of AAPL and the execution provider reports an execution of 700 shares, the message is formatted correctly but the data is unexpected.
FIXSIM allows users to create both expected and unexpected messages to ensure both sides of the interface handle exceptions. Testing business logic requires the flexibility to create and modify messages to simulate scenarios.
Manual Testing
With our web-based portal, easily configure and monitor FIX message traffic. See orders and execution messages and control how orders are executed.
Message Views
View message traffic in raw FIX format as well as translated tag numbers and values.
Blotter Views
Trade blotter views provide a trader’s viewpoint on active orders. See order quantities, average prices, and execution values. Take action on orders with workflows like partially fill, cancel, correct prices, and more.
Automated Testing
Automated FIX testing helps ensure ongoing compliance with integrations. Build and run repeatable test cases with FIXSIM.
Rule Builder
Build rules and actions to respond to messages. Example: if an order is received in FIXSIM for IBM, acknowledge the order, partial fill, and cancel remaining quantity. Configure FIXSIM sessions to your testing scripts to provide user-free automation.
RESTful API
Control FIXSIM via RESTful calls (e.g. Curl). Using Swagger/OpenAPI, our API is documented and can generate a client in many languages (C#, Java, Ruby, and more).
How It Works
FAQ
Using FIXSIM for Testing
FIXSIM was designed to be a web-based solution that requires no software downloads. Simply connect your FIX engine to FIXSIM and manage your FIX sessions via our web portal. FIXSIM is the work of many years experience integrating FIX trading destinations.
With month-to-month pricing, you can start testing immediately with no long-term contracts.
On-demand FIX testing via the Web
Try FIXSIM!
Customer Recommendations Join the hundreds of customers who use FIXSIM. We're also our own customer!
"We started with our UK QA team, now rolled out to global teams!"
"Essential to help us stress test clients accessing our Dark Pool"
"As a contractor, I use FIXSIM for helping build FIX solutions for my clients."
