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FIX Client Simulator 3.13.0 was released on 21.01.2026
New Features and Improvements
The FIX Client Simulator 3.13.0 release introduces a configurable Grid View for the events. Previously, INFO and FIX messages were displayed as plain text in a List View, which made long event streams hard to read. A new configurable Grid View provides a structured, table-like layout. It also allows you to configure the view by right-clicking on the columns, including highlighting specific FIX tags for easier navigation and readability. To switch between List View and Grid View, we added a checkbox at the bottom (Grid View) that lets you toggle between the two views.
FIX Client Simulator 3.12.0
FIX Client Simulator 3.12.0 was released on 02.07.2025
Fixed Bugs
Fixed issue with invalid FIX message, now all the errors are shown in the Events Viewer
FIX Client Simulator 3.11.0
FIX Client Simulator 3.11.0 was released on 05.02.2025
New Feature
The FIX Client Simulator 3.11 release introduces Kafka session integration, supporting existing features - the Send Message Tab, Auto-increment and Replay Logs - to work seamlessly with Kafka. The FCS Kafka session supports the following functionality: Producer & Consumer Creation Create, configure, and save Kafka producer or consumer sessions. Configure topics, groups, optional keys, and more. Authentication & SSL/TLS Supports SASL/Plain (username/password) or no authentication. Optional SSL/TLS encryption with the ability to validate certificates. Send Message Tab User can send or receive a FIX message or arbitrary text (non-FIX content) via Kafka sessions. FIX-specific features (like the context-driven workflows, validation, and auto-increment) are supported but require proper FIX tag=value formatting. Auto-increment Automatically increment fields (e.g., sequence numbers) in FIX messages, just like in FIX sessions. Replay Logs Replay FIX message logs using Kafka session, facilitating troubleshooting, performance review, and re-testing.
FIX Client Simulator 3.10.0
FIX Client Simulator 3.10.0 was released on 24.09.2024
New Features and Improvements
The FIX Client Simulator 3.10.0 release introduces the "Backup Connection Parameters" section, which allows configuring a backup connection to ensure a seamless transition if the primary connection fails. "Enable Cyclic Switch Backup Connection" will cyclically try to reconnect to the primary and backup if either is lost "Enable Auto Switch to Backup Connection" automatically switches to the backup if the primary fails after a few attempts. If disabled, no backup attempt will be made "Keep Connection State" retains the same log files for both connections if enabled. If disabled, separate logs will be created for the backup connection
In the FIX Client Simulator 3.10.0 release, the Message Details window has been enhanced with the following features: Added a tag search functionality, allowing users to find tags by number through the auto-search bar located at the top of the window. Implemented the ability to add and remove tags directly within the interface. Tag information (number, name, value) is now displayed in a simplified and organized format, accompanied by actionable icons.
FIX Client Simulator 3.9.0
FIX Client Simulator 3.9.0 was released on 24.06.2024
New Features and Improvements
The FIX Client Simulator 3.9.0 release introduces a multiline session display option within the Session list. Previously, session details were confined to a single row, causing readability issues. This update allows to enable "Multiline Session Display" through the Options menu. This functionality allows users to have control over how they view session information.
With FIX Client Simulator 3.9.0 release it is possible to access detailed message information within the Event Viewer. By right-clicking on a specific message and selecting "View FIX Message" a dedicated window launches, presenting comprehensive message data in a structured table format. This window offers the functionality to collapse and expand sections containing repeating groups, allowing users to efficiently navigate and analyze message content.
FCS Console now offers the ability to replay log files and the "Help" command has been expended for detailed guidance. The available options for log replay customization are the following and they allow to: Log File: Specify the precise log file to be used for the replay. Repeats: Define the number of times you want to replay the chosen log file. Speed Multiplier: Adjust the replay speed to run faster or slower than the original session. Message/Second: Control the message rate during replay based on timestamps within the log file. Sequence Numbers: Choose which sequence numbers to process or exclude from the replay. Message Filtering: Select specific message types to include or exclude from the replay process. Session Timeout: Set the maximum wait time for establishing the replay session to avoid unnecessary delays.
FIX Client Simulator 3.8.0
FIX Client Simulator 3.8.0 has been released on Feb 8, 2024
New Features and Improvements
FIX Client Simulator now provides the ability to select incoming Order Single (35=D) message in the Events Viewer section and automatically form the Execution Report (35=8) with 39=8 to send in running Initiator or Acceptor session (reject).
When working on test scenarios at the stages “Expect”, “Expect Until”, and “ExpectThenSend”, the tags that go into specific repeating groups can already be validated, not just based on a particular tag but also with an asterisk (*) instead of 0,1,2, etc.
FIX Client Simulator now has Balance quantities checkbox which allows checking the messages “Partial Fill” and “Fill”, balance 32, 14, 151 tags by filling empty values with correct values according to the order flow when "Balance order quantities" is set and incoming message is New Order Single. If Partly Fill, and Fill do not contain some of tags 32, 14, 151, the tags will be added. If the user sets some of the tags to have an incorrect value (too big or too small), the tags will be filled in with correct values. Additionally, tag 6 (AvgPx) is being calculated.
FIX Client Simulator now has been updated with button “duplicate command” as well as other commands have been changed to icons instead of wording.
Coloring on the active test scenario button has been added to make it easier to define the running scenario among others as well as the name of the running session is being displayed under “Session” column.
With 3.8.0 release it is already possible to manually configure the delays between messages in ExpectThenSend command Parameter. Additionally, the random delay interval can be set up with minimum and maximum values as well as fractional values are possible for seconds.
Now the horizontal scroll bar will be displayed in Event viewer only when it’s needed.
Fixed Bugs
Fixed issue with test execution time being displayed incorrectly if it is higher than 1h
Fixed issue with error message not being shown when user trying to run Test Scenario after scenario file being deleted
FIX Client Simulator 3.7.0
FIX Client Simulator 3.7.0 has been released on Dec 7, 2023.
New Features and Improvements
FIX Client Simulator now provides the ability to autogenerate the Order Status Request (35=H) message for incoming New Order Single (35=D) and outgoing Execution Report (35=8) messages in the Events Viewersection. The new message will be autogenerated according to the attached FIX dictionary file using the tag values present in the initial FIX message. The autogenerated Order Status Request (35=H) message will be added to the Send Message section.
FIX Client Simulator now provides the ability to autogenerate the Execution Report (35=8) for incoming Order Status Request (35=H) messages in the Events Viewer section. The new message will be autogenerated according to the attached FIX dictionary file using the tag values present in the initial FIX message. The autogenerated Execution Report (35=8) message will be added to the Send Message section.
FIX Client Simulator now provides the ability to autogenerate the Order Cancel Reject (35=9) message for the incoming Order Cancel Request (35=F) and Order Cancel/Replace Request (35=G) messages in the EventsViewer section. The new message will be autogenerated according to the attached FIX dictionary file using the tag values present in the initial FIX message. The autogenerated Order Cancel Reject (35=9) message will be added to the Send Message section.
It is possible now to configure FIX sessions using TLS v1.3 protocol version.
The OnMessage handler now provides the ability to specify, whether messages from the Then Send section must be sent: with the specified probability immediately with the specified delay with the random delay
FIX Client Simulator now provides the ability to generate values in different formats for tags in the Command Parameter window while creating a new Test Scenario: guid - ${guid} number - ${random(0, 10)} current timestamp - ${timestamp}
FIX Client Simulator now provides the ability to define the path to the system directory where all created Test Scenarios will be stored. The new optional TestScenarioFolder property is added to the Fcs.exe.config configuration file.
FIX Client Simulator now provides the ability to copy FIX messages from the Events Viewer section to the clipboard without timestamps. To copy the message from the Events Viewer section to the clipboard without a timestamp this message must be right-clicked on and then the Smart Copy action must be selected in the Context Menu. The Smart Copy action also allows copying the whole message even if only its part is selected.
Fixed Bugs
Fixed the issue when FIX Client Simulator could not be closed correctly when 1M messages were sent.
Fixed the issue when FIX Client Simulator didn't check the user's RO permissions to replay log files on Linux.
FIX Client Simulator 3.6.0
FIX Client Simulator 3.6.0 is released on Nov 3, 2023.
New Features and Improvements
The new OnMessage handler is introduced enabling users to define the Expect Then Send instruction. This instruction will be executed in the infinite loop simulating FIX messages flow.
Events and messages in the Events Viewer section now can be filtered using the Filter text field. All special symbols are supported except '/'.
FIX Client Simulator allows customizing the title of the main application window by defining the MainWindowTitle property in the Fcs.exe.config file.
Fixed Bugs
Fixed the issue when the outgoing Heartbeat(35=0) message was displayed twice in the Events Viewer section.
Fixed the issue when the Reject(35=3) message wasn't displayed in the Events Viewer section when the unexpected Resent Request message(35=2) was received.
Fixed the issue when FIX Client Simulator allowed the creation of multiple FIX sessions with identical names.
Fixed the issue when the values of the Rate and Send count fields could not be set to defaults.
Fixed the issue when the Allow message resending flag was not functioning correctly.
Fixed the issue when FIX Client Simulator continued sending messages to the deleted FIX session.
FIX Client Simulator 3.5.0
FIX Client Simulator 3.5.0 is released on Sep 15, 2023.
Package Improvements
FIX Client Simulator is now available on Ubuntu Linux 22.04 and Rocky Linux 8.
FIX Client Simulator is now available on macOS.
FIX Client Simulator 3.4.0
FIX Client Simulator 3.4.0 is released on Aug 2, 2023.
New Features and Improvements
FIX Client Simulator now provides the ability to manually create, automatically record and run created test scenarios in the new Test Scenarios tab added to the main FCS screen. Also, it is possible to Edit, Rename and Remove existing test scenarios. Please refer to the Create and run test scenarios for more details.
FIX Client Simulator 3.3.0
FIX Client Simulator 3.3.0 is released on Jul 4, 2023.
New Features and Improvements
FIX Client Simulator now provides the ability to autogenerate Order Cancel Request (35=F), Order Cancel/Replace Request (35=G) messages for outgoing New Order Single (35=D) and incoming Execution Report (35=8) messages in the Events Viewer section. The new message will be autogenerated according to the attached FIX dictionary file using the tag values present in the initial FIX message. The autogenerated message will be added to the Send Message section.
FIX Client Simulator now provides the ability to autogenerate New, Partially Filled, and Filled Execution Report (35=8) for incoming New Order Single (35=D) messages in the Events Viewer section. The new message will be autogenerated according to the attached FIX dictionary file using the tag values present in the initial FIX message. The autogenerated message will be added to the Send Message section.
FIX Client Simulator now provides the ability to restore session log files in the Events Viewer section after the session restart. The new DaysToKeepEventViewLogs property defining the number of days for which the session logs must be restored is added to the Fcs.exe.config file.
FIX Client Simulator now provides the ability to copy the whole FIX messages or only their parts from the Events Viewer section to the clipboard. To copy the whole message from the Events Viewer section to the clipboard this message must be right-clicked on and then the Copy Message action must be selected in the Context Menu. To copy the part of the message from the Events Viewer section to the clipboard this part of the message must be selected/highlighted and right-clicked on and then the Copy action must be selected in the Context Menu.
Fixed Bugs
Fixed the issue when the Autoincrement tags functionality worked incorrectly when the autoincremented tag was inside of the repeating group.
Fixed the issue when FIX Client Simulator could not send a custom Logon message if the AdditionalParsersList property was specified with the 'ADD@FIXT11:FIX44' value.
FIX Client Simulator 3.2.0
FIX Client Simulator 3.2.0 is released on May 29, 2023.
New Features and Improvements
FIX Client Simulator now does not reset selected tag values auto-incrementation in the following cases: When a new message was added or the old message was deleted from the Send Message section. When the message was changed in the Send Message section, even if this message became non-parsable (e.g. the SOH symbol was added near another SOH). When the value of the auto-incrementing tag was changed for the message in the Send Message section.
FIX Client Simulator now provides the ability to copy only part of the FIX message (e.g. tag=value or only value) from the Events Viewer section. In such a case, the selected text will be highlighted in blue, and the whole message will be highlighted in white.
The new StoreSettingsInCurrentWorkingFolder property was added to the Fcs.exe.config configuration file. This property defines whether the user.config file must be stored in the default or current working directory. To store the user.config configuration file in the current working directory the StoreSettingsInCurrentWorkingFolder property must be set to 'true'.
FIX Client Simulator 3.1.0
FIX Client Simulator 3.1.0 is released on Apr 12, 2023.
The ability to set the initial tag value for auto-increment.
FIXLatest application version support.
Fixed Bugs
Fixed the issue when FIX Client Simulator could not send FIX 5.0 messages when the 1128 tag was not specified.
Fixed the issue when FIX Client Simulator displayed a console error when the main application window was resized.
Fixed the issue when FIX Client Simulator could not generate new application messages with the FIX50 version.
Fixed the issue when the FIX message containing another FIX message was not parsed correctly in the Replay log files functionality.
Fixed the issue when FIX Client Simulator incorrectly counted FIX messages when the log file with spaces or empty lines was replayed.
Fixed the issue when the splash screen was displayed with delay.
Fixed the issue when the message color disappeared in the Events Viewer section after maximizing the application window.
Fixed the issue when FIX Client Simulator did not replay log messages if the timestamp was added to the Send Message tab.
Fixed the issue when FIX Client Simulator incorrectly identified the beginning of the message in the Send Message tab.
Fixed the issue when FIX Client Simulator could not recreate a session using a custom dictionary if the previous session with the same name was non-gracefully terminated.
FIX Client Simulator 3.0.0
FIX Client simulator 3.0.0 is released on Oct 11, 2022.
New features and improvements
To use this functionality a log file must be loaded to FIX Client Simulator and particular message(s) from this file must be selected in the Send Message tab.
The ability to send the selected message(s) and automatically select the next message for sending was added.
Fixed bugs
Fixed the issue when some symbols (i.e. №) were sent incorrectly while replaying the log file.
Fixed the issue when FIX Client Simulator crashed for FIX sessions with FIX 5.0SP2 version while using the wrong dictionaries.
Fixed the issue when some symbols were sent incorrectly if the message was created from the template.
Fixed the issue when incoming Resend Request(2) messages were not shown in the FIX Client Simulator.
Fixed the issue when a corrupted in/out log file was created for the admin session if the FIX Client Simulator was connected to FIXICC.
FIX Client Simulator 2.30.0
FIX Client Simulator v.2.30.0 is released on Aug 19, 2022
New Features and Improvements
The ability to use pipe delimiter for tags in FIX message in the 'Send Message' tab.
The ability to save the FIX message as a file via context or main menu.
The ability to load FIX messages in the 'Send Message' tab from the file.
Fixed bugs
Fixed the issue when long FIX messages could not be shown in the Events Viewer window.
Fixed the issue when FIX Client Simulator displayed an unclear parsing error when the user sent an invalid message.