# Open Source License

Emscripten is made available under two permissive open source licenses: the MIT license and the University of Illinois/NCSA Open Source License.

There is little, if any, practical difference between the licenses. They are both offered because the:

- MIT license is well known and understood.

- University of Illinois/NCSA Open Source License allows Emscripten’s code to be integrated upstream into LLVM, should the opportunity arise.

The license for Emscripten 6.0.5 (dev) is reproduced below. The current full license can be found on GitHub (and is also present in the root of the SDK).

    Emscripten is available under 2 licenses, the MIT license and the
    University of Illinois/NCSA Open Source License.

    Both are permissive open source licenses, with little if any
    practical difference between them.

    The reason for offering both is that (1) the MIT license is
    well-known, while (2) the University of Illinois/NCSA Open Source
    License allows Emscripten's code to be integrated upstream into
    LLVM, which uses that license, should the opportunity arise.

    The full text of both licenses follows.

    ==============================================================================

    Copyright (c) 2010-2014 Emscripten authors, see AUTHORS file.

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    THE SOFTWARE.

    ==============================================================================

    Copyright (c) 2010-2014 Emscripten authors, see AUTHORS file.
    All rights reserved.

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the
    "Software"), to deal with the Software without restriction, including
    without limitation the rights to use, copy, modify, merge, publish,
    distribute, sublicense, and/or sell copies of the Software, and to
    permit persons to whom the Software is furnished to do so, subject to
    the following conditions:

        Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimers.

        Redistributions in binary form must reproduce the above
        copyright notice, this list of conditions and the following disclaimers
        in the documentation and/or other materials provided with the
        distribution.

        Neither the names of Mozilla,
        nor the names of its contributors may be used to endorse
        or promote products derived from this Software without specific prior
        written permission.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
    IN NO EVENT SHALL THE CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR
    ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
    SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE SOFTWARE.

    ==============================================================================

    This program uses portions of Node.js source code located in src/library_path.js,
    in accordance with the terms of the MIT license. Node's license follows:

        """
            Copyright Joyent, Inc. and other Node contributors. All rights reserved.
            Permission is hereby granted, free of charge, to any person obtaining a copy
            of this software and associated documentation files (the "Software"), to
            deal in the Software without restriction, including without limitation the
            rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
            sell copies of the Software, and to permit persons to whom the Software is
            furnished to do so, subject to the following conditions:

            The above copyright notice and this permission notice shall be included in
            all copies or substantial portions of the Software.

            THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
            IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
            FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
            AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
            LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
            FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
            IN THE SOFTWARE.
        """

    The musl libc project is bundled in this repo, and it has the MIT license, see
    system/lib/libc/musl/COPYRIGHT

    The third_party/ subdirectory contains code with other licenses. None of it is
    used by default, but certain options use it (e.g., the optional closure compiler
    flag will run closure compiler from third_party/).