Page ContentsPage Contents (click to expand)
  1. Known Limitations
    1. Debugging:
    2. Capabilities:
  2. WebAssembly modules usage
  3. File Access
  4. Debugging


In order to provide both security and portability, it was decided to move away from add-ons distributed as DLLs in favour of add-ons distributed as WebAssembly modules. In order to do so without requiring a full rewrite of existing add-ons, a new platform toolset was designed for Visual Studio with the following capabilities:

While WebAssembly itself is well documented, there seems to be some confusion as to how WebAssembly modules can be run outside of a web environment. To clear a few misconceptions:


To help you understand the capabilities of using WASM and the functions that are available to you, please see the following sections:



Known Limitations

With the current releases of the game and SDK, the following limitations exist:







WebAssembly modules usage

A WebAssembly module can be used by Microsoft Flight Simulator in two different ways:


In both cases the game will look for and execute the following module functions if they exist:



File Access

In order to access files from within an add-on, filenames can be prefixed in two ways:




Here are the steps to follow to debug your add-on:

NOTE: your WebAssembly module must be compiled in Debug mode for C/C++ code and symbols to be visible while debugging.




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