Important: Please read the Qt Code of Conduct -

Qt for WebAssembly binaries for Mac OS

  • Hi,

    I have followed the instructions for installing Qt for WASM in Mac OS but I am unable to make it work. I have also tried in Linux but failed also.

    I have heard there are Qt for WASM binaries but I cannot find them.
    Please could you provide me with a URL to download them?

    Thank you very much in advance for your help,


    Re: Qt for WebAssembly

  • Lifetime Qt Champion

    Hi and welcome to devnet,

    The online installer provides them or you can also get them using the MaintenanceTool application.

  • I found it is easier to recompile Qt for WASM on MacOS. Qt requires specific version of emsdk to be installed, like 1.39.30 for multithreaded support. MacOS supplies older Python with older OpenSSL, so you'll have to do something anyway, I decided to rebuild Qt from source.

    I recall that I had to follow steps rather carefully - install emsdk, activate emsdk, source, and then use proper qmake.

    I tried to use Qt Creator, starting from v4.11, but have not had much success. Command line however works well for me.

    I had no issues at all with Qt for WASM binaries on Linux, as long as steps related to emsdk were followed - install/activate/source. Still in terminal.

  • You need to explicitly enable the webassembly plugin.
    From the menu: QtCreator->About plugins->Device Support->WebAssembly (experimental)

    Depending on your version of emscripten that you installed, it may or may not successfully detect the emscripten compiler.

Log in to reply