FIX Protocol Simulator

Simulate FIX Protocol Message Exchange.

Connect & Simulate Your FIX Protocol Application!

Join for free and try FIXSIM, our web based FIX simulator.

What is a FIX Simulator?

A FIX simulator is a tool used for testing FIX Protocol integrations. The FIX protocol is a community driven standard that outlines the message format and procedures for exchanging financial information. A FIX Simulator can provide acceptance of a FIX connection (act as a FIX Acceptor) or initiate a connection (act as a FIX Initiator).

A FIX protocol simulator is required to act as “the other side of the trade”. For instance, if you are an asset manager, you will need a FIX protocol simulator to act as a broker/dealer or exchange to simulate order execution. Conversely, if you are a broker/dealer, you need a FIX client simulator to behave as a client connecting and submitting orders to you.

How FIXSIM is Different

FIXSIM is a web-based solution that can either act as a FIX initiator or acceptor (or both!). With no software to download and simple month to month plans, get immediate access to a FIX testing endpoint for your needs.

We support equities, futures/options, foreign exchange, fixed income, and other asset classes with ANY version of FIX. From our web portal, quickly build out any FIX simulator session and connect your application.

Manual FIX Protocol Testing

With our web-based portal, easily configure and monitor FIX message traffic. See orders and execution messages and control how orders are executed.

FIX Message Views

See direct FIX message traffic and view messages in raw FIX format as well as translated tag numbers and values.

Blotter Views

Our trade blotter views provide you with a trader's viewpoint on active orders. See order quantities, average prices, and execution values. Take action on orders in the blotter with actions like: Partially fill, cancel, correct prices, and more right from the web portal.

Automated Testing

Having an automated solution to FIX testing provides assurance you maintain compliance with FIX integrations. Build, design, and repeatable FIX simulator cases with FIXSIM.

Rule Builder

Use our web portal to build rules and actions to respond to messages. For example, if an order is received in FIXSIM for IBM, acknowledge the order, partial fill, and cancel the remaining quantity. Configure your FIXSIM sessions to your testing scripts to provider user free automation.


We offer our Web API to directly control FIXSIM via RESTful calls (e.g. Curl). Using Swagger/OpenAPI, our API is fully documented and can easily generate a client in any language (C#, Java, Ruby, more). This provides you with the full power of FIXSIM to be controlled by your application.

On-demand FIX Simulator via the Web.

Join for free and 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!"

Quality Assurance Lead / Fintech Vendor

"Essential to help us stress test clients accessing our Dark Pool"

CEO / US Equity Exchange

"As a contractor, I use FIXSIM for helping build FIX solutions for my clients."

Software Contractor / London

FIX Protocol Client Testing

99.9% Uptime Web Based Fully Responsive Monthly Subscriptions