What is SimConnect, and how do I use it in MSFS?

SimConnect is Microsoft Flight Simulator’s built-in API for exchanging simulation data and commands with compatible PC programs. It powers moving maps, hardware bridges, logbooks and motion software. To use it, run a compatible app alongside a loaded MSFS flight; there is normally nothing to install or enable separately.

What does SimConnect actually do?

SimConnect is a client-server interface: Microsoft Flight Simulator supplies the server, while an external utility acts as the client. The client can subscribe to simulator variables, receive events and send supported commands back to the aircraft or simulator.

• Moving maps and flight loggers read position, altitude, speed, heading and flight-state data.
• Hardware bridges read cockpit displays and translate knobs or switches into simulator events, as shown in our worked setup for Logitech and Saitek radio panels.
• Motion and telemetry software reads acceleration, attitude and other flight data.
• Traffic and automation tools can use supported events, writable variables and AI-object functions.

SimConnect is not an add-on manager, controller driver or aircraft installer. It also does not expose every system in every aircraft. Complex add-ons often use custom local variables, custom events or a WASM bridge because standard SimConnect variables do not cover their proprietary systems.

Microsoft Flight Simulator 2020 and Microsoft Flight Simulator 2024 share much of the SimConnect model, but compatibility is not automatic. An app should explicitly support the simulator generation and aircraft you intend to use.

Do I need to install or enable SimConnect?

For a normal local connection on Windows PC, SimConnect is already included with Microsoft Flight Simulator and has no master switch. Developer Mode and the full SDK are not required merely to connect an existing utility.

Some older applications require a legacy SimConnect runtime. If the application’s own installer supplies that prerequisite, install the bundled version. Do not download an unidentified SimConnect.dll or copy DLL files into the simulator folders, as different clients may depend on different side-by-side runtimes.

These instructions apply to Windows PC. Xbox editions and the PlayStation 5 edition of MSFS 2024 cannot run ordinary Windows SimConnect companion apps or expose their configuration files; hardware or services must specifically support the console concerned.

How do I use SimConnect with an add-on?

End users use SimConnect through the controls of a compatible add-on rather than through an MSFS menu.

1. Check compatibility. Confirm that the utility supports Microsoft Flight Simulator 2020 or 2024 as appropriate. Check aircraft support as well if it controls detailed cockpit systems.
2. Install the client application. Allow its installer to add any documented runtime or in-simulator module. A WASM module may need to go into the MSFS Community folder, but only when the application specifically provides one.
3. Start Microsoft Flight Simulator. Load into an aircraft at an airport. Some clients connect from the main menu, but meaningful aircraft data may not appear until the flight has loaded.
4. Open the companion application. Select MSFS or SimConnect if it offers several simulator types. A local client normally discovers the simulator automatically.
5. Verify the connection. Look for a connected status, changing altitude or position data, or a working test control. Use a default aircraft first when diagnosing compatibility.

Launch order usually does not matter because many clients wait for MSFS to become available. If manual launching works and you want the app started automatically, follow our safe method for adding and checking exe.xml launch entries.

Using SimConnect as a developer

Developers use the SimConnect documentation, libraries and samples supplied through the SDK for the relevant simulator. End users do not need these development files; if you are building a client, our guide explains where the MSFS SDK comes from and how its tools fit together.

Can SimConnect run over a network?

Yes, a SimConnect client can run on another Windows computer on the same local network, but remote connections need extra configuration.

With raw remote SimConnect, the simulator computer acts as the server. Its settings are normally held in SimConnect.xml, while the remote client reads SimConnect.cfg or equivalent connection settings. File locations differ between simulator editions and installation types.

Both sides must use the same port and protocol. The client needs the simulator PC’s LAN address, not 127.0.0.1, and the selected port must be allowed through the firewall on a private network. Do not expose a SimConnect port directly to the internet. Some utilities use their own network bridge instead, in which case their documented method takes priority.

Why is SimConnect not connecting?

Most SimConnect failures come from an unsupported client version, a flight that has not loaded, an unnecessary custom configuration or a blocked remote connection.

1. Test after loading a flight. A client may find the simulator at the menu yet receive no aircraft data until the cockpit is active.
2. Try a default aircraft. If basic position data works but switches or displays do not, the chosen aircraft probably uses custom variables that the client does not support.
3. Confirm the simulator version. Update or replace a client that supports MSFS 2020 but not MSFS 2024, or vice versa.
4. Return local connections to their default state. Local clients normally need no edited SimConnect.xml. Back up and temporarily remove only configuration files that you added yourself.
5. Install documented prerequisites. An error about loading SimConnect may mean an older utility needs the legacy runtime included by its installer.
6. Check remote addressing and security. Verify the server’s LAN address, matching port, private-network firewall permission and any security software that has quarantined the client.
7. Run one client at a time. Close traffic tools, panel bridges, loggers and other companions, then reconnect the failing app by itself.

For file locations, legacy runtimes and network configuration, use our detailed SimConnect installation and connection repair procedure.

Can SimConnect cause stutters or control conflicts?

SimConnect itself is not usually the cause of poor performance, but a client can create problems by requesting data every frame, injecting large amounts of traffic or repeatedly writing control events.

If stutters disappear when companion apps are closed, restart them individually and reduce telemetry, update or traffic rates where those settings exist. If radios snap back, controls twitch or the autopilot disconnects, check for two clients—or a client and an MSFS binding—sending the same command. Keep only one active source for each affected control.