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

SimConnect is Microsoft Flight Simulator’s built-in API for exchanging live simulation data and commands with compatible PC programs. It powers moving maps, logbooks, hardware bridges, traffic tools and motion systems. To use it, run a compatible app alongside a loaded MSFS 2020 or MSFS 2024 flight; nothing is normally installed or enabled separately.

What does SimConnect actually do?

SimConnect provides a client-server connection between Microsoft Flight Simulator and external software. MSFS supplies the server, while each client requests selected data, subscribes to changes and sends supported commands instead of extracting information from the screen or simulator files.

• Moving maps and flight loggers read position, altitude, speed, heading, fuel use and flight-state data.
• Hardware bridges drive displays and translate physical switches, knobs or buttons into simulator events. Our guide to setting up Stream Deck with Microsoft Flight Simulator shows how live data and switch-state feedback can be used.
• Motion and telemetry software reads attitude, acceleration and other flight data.
• Traffic utilities create, remove or monitor supported AI aircraft and ground objects.
• Automation tools monitor aircraft or environmental conditions and write permitted values.

Clients can also receive system events when a flight loads, pauses or ends. Some variables are read-only, and a client may request updates at a chosen frequency rather than repeatedly reading the entire simulator state.

SimConnect is not an add-on manager, controller driver, aircraft installer or standalone application. Liveries and most scenery packages do not need it because MSFS loads them directly.

Can SimConnect control every aircraft system?

No; SimConnect can control only the variables, input events and functions exposed by the simulator or aircraft.

Standard systems such as lights, landing gear, flaps and some autopilot functions often respond to normal events. Complex aircraft may instead use local variables, HTML/JavaScript components, custom input events or proprietary code. They may require an aircraft-specific profile, Community package or WASM bridge.

This explains a common failure pattern: position and altitude update correctly, but a custom FMS, display or autopilot mode does nothing. The SimConnect connection is working; the client simply lacks support for that aircraft-specific system.

Do I need to install or enable SimConnect?

No, not for a normal local connection on a Windows PC. SimConnect is included with the PC versions of Microsoft Flight Simulator 2020 and Microsoft Flight Simulator 2024, has no master enable switch and does not require Developer Mode or the full SDK.

Install every component supplied with the client application. Some products need both an external executable and a module in the MSFS Community folder. Older FSX-era programs may also require a legacy SimConnect runtime supplied by their installer.

Do not download an unidentified SimConnect.dll or copy DLL files into simulator folders. Different clients can depend on separate side-by-side runtimes, and replacing files manually can break another application. Our SimConnect installation and repair procedure covers legacy runtimes, file locations and safe recovery steps.

Ordinary Windows SimConnect companion apps cannot run on Xbox Series X|S or with MSFS 2024 on PlayStation 5 or PS5 Pro. Console hardware and services must explicitly support the relevant platform.

How do I use SimConnect with an add-on?

End users operate SimConnect through a compatible application rather than through an MSFS menu.

1. Check compatibility. Confirm that the utility supports MSFS 2020 or MSFS 2024 as appropriate. Similar APIs do not guarantee support for both generations, and detailed cockpit controls may also require an aircraft-specific profile.
2. Install all supplied components. Allow the installer to add documented runtimes, plug-ins or Community packages. Add a WASM module only when the application provides and requires one.
3. Load a flight in MSFS. Some clients connect at the main menu, but useful aircraft data may not appear until the cockpit is active.
4. Open the companion application. Select MSFS or SimConnect if it supports several simulators. A local client normally discovers the simulator automatically.
5. Verify live data. Look for a connected status, changing position or altitude, or a working test control. Use a default aircraft first when checking basic compatibility.

Launch order usually does not matter because many clients wait for MSFS. If a failed client remains stuck after the flight loads, close and reopen it. Once manual launching works, our method for adding and checking an exe.xml launch entry safely explains how to start it automatically.

Using SimConnect as a developer

Developers use the SimConnect documentation, libraries and samples supplied through the relevant simulator SDK. End users do not need these files; anyone building a client can use our explanation of how the MSFS SDK and its development tools fit together.

Can SimConnect run over a network?

Yes, a SimConnect client can run on another Windows computer on the same local network, although remote connections require configuration. A local connection does not need internet access.

For raw remote SimConnect, the simulator computer acts as the server. Its settings are normally stored in SimConnect.xml, while the remote client uses SimConnect.cfg or equivalent settings. Locations vary by simulator edition and installation type.

Use the simulator PC’s LAN address, not 127.0.0.1, and permit the selected port through the firewall on a private network. Never expose a SimConnect port directly to the internet. If an application supplies its own network bridge, follow that method instead.

Why is SimConnect not connecting?

Most connection failures are caused by client compatibility, missing supplied components, an unloaded flight or incorrect remote settings—not a disabled option in MSFS.

1. Load an actual flight. A client can detect MSFS at the menu yet remain on “waiting for simulator” until simulation data becomes available.
2. Restart the client. Reopen it after the cockpit has loaded, particularly if it failed while MSFS was starting or updating.
3. Try a default aircraft. If basic flight data works but switches or displays do not, the original aircraft probably uses unsupported custom systems.
4. Confirm version support. Update or replace a client that supports MSFS 2020 but does not recognise MSFS 2024, or vice versa.
5. Install documented prerequisites. Check for a required Community module, plug-in or legacy runtime from the application’s installer.
6. Restore local defaults. Local clients normally need no edited SimConnect.xml. Back up and temporarily remove only custom configuration files that you added.
7. Check remote addressing. Verify the simulator PC’s LAN address, matching protocol and port, private-network firewall permission and any security software quarantine.
8. Isolate other clients. Close traffic tools, loggers and hardware bridges, then test the failing application alone.

Can SimConnect cause stutters or control conflicts?

SimConnect itself normally has little noticeable performance cost, but a client can cause stutters by requesting data every frame, injecting heavy traffic or sending commands repeatedly.

If frame pacing improves when companions are closed, restart them individually and reduce telemetry, traffic or update 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—controlling the same function. Keep one active command source for each affected control.