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Suppose I use this ActionScript API released under MIT license to build a software: http://www.cove.org/ape/docs/api/

  1. Can I sell that software?
  2. Do I need to give the source code of my software away?
  3. Is anyone receiving my software permitted to resell the software?

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157
  1. You can sell the software.
  2. No, you are not compelled to provide source code.
  3. Anyone who receives source code may do as the license permits. This does not extend to binary distributions.

Read the MIT license. Read the whole thing and understand it. It was meant to be read by ordinary people, unlike other licenses that are very complex:

Copyright (c) year copyright holders

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.

  • 3
    I agree, read the license, it's short: opensource.org/licenses/mit-license.html – Ben Blank Apr 1 '09 at 18:32
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    Jox, I pasted the ENTIRE license above so you can see for yourself. BSD/MIT/ISC style licensed software have been included in Mac OS, Windows, etc... You cannot remove the license/copyright, but you can do pretty much anything else. It's not viral. – dwc Apr 2 '09 at 15:19
  • 18
    As a non-native English speaker, I've been confused by the MIT license as well. The confusion stems from the fact that the license talks about the 'Software' to which the license applies. So if I link to MIT-licensed 'Software' and distribute a derivative + MIT license (mandatory) then this implies that the derivative would become the 'Software' according to the license. To be clear: there is no mention of source code\binary distribution anywhere, just 'Software'. – pauluss86 Jul 7 '13 at 17:37
  • 50
    Even as a native speaker, I found it difficult to understand. If the permission notice has to be included in all copies of the software, and if compiled binaries are still "copies of the software", then seemingly the permission notice has to be included with your compiled binaries. If you are including the permission notice, then seemingly you are giving recipients permission to copy "the software" -- i.e. both the MIT-licensed library software and your own software together. I know that this is not the intent of the license ... but still, it is confusing to the literal minded such as myself. – William Payne Aug 12 '13 at 16:33
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    You ask that people read the license, but nowhere do I see support for your point (3) that the license rights only transitively extend to people receiving source copies of the software, rather than binary copies. In fact, there is no distinction at all between "source" and "binary" at all in the license. Furthermore, software is commonly understood as meaning both the source and binary forms when considering the notice clause, so it be very odd for it to have the opposite meaning elsewhere in the license. – BeeOnRope Jun 17 '16 at 22:45
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According to "Understanding Open Source and Free Software Licensing" by By Andrew M. St. Laurent:

These licenses, as applied to the original licensed code, allow that code to be used in proprietary software and do not require that open source versions of the code be dis- tributed. Code created under these licenses, or derived from such code, may go “closed” and developments can be made under that proprietary license, which are lost to the open source community. For the same reason, however, these licenses are very flexible and compatible with almost every form of open source license.

  • 6
    They should really spell out that you can distribute the compiled software without distributing the MIT license, and that you can distribute your own source code that uses the MIT-licensed software, with the MIT license only applying to the MIT-licensed software. i.e.The MIT license just protects the stuff it licenses, and does not make your additional work that works with that code need to be MIT-licensed too. Almost everyone who attempts to explain licenses doesn't go into those points. – Dronz Nov 1 '18 at 18:03
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As always, consult a lawyer. If this library is released strictly using the MIT license then:

(i) Yes, you can sell your software provided you include the MIT license as part of your product. (ii) No, you don't have to share your code with the community but it would be nice. (iii) Yes, reselling is permitted.

MIT License:

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.

  • 4
    "As always, consult a lawyer." This is extremely impractical advice for a great deal of situations. – Sid Oct 8 '18 at 20:48
  • 1
    With any sort of commercial business dealing with licensing however it can be a great quote to keep in mind. I don't think he literally means always consult a lawyer – Riley Carney Mar 15 at 18:21

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