Frequently Asked Questions about the permissive free software MIT license. The MIT license is more precisely named the Expat License.
Can I use MIT-licensed code commercially?
Yes. There are no restrictions on commercial use.
Can I use MIT-licensed code in closed-source software?
Yes, however the copyright notice and permission notice must be included in the documentation or EULA of your Software. e.g. "This software uses <library name> - see library-license.txt"
What if my project has no documentation or 'about' feature?
Contact the author. If the author agrees, a notice on your product website may suffice as documentation.
Can I redistribute MIT-licensed code under another license?
Yes. You cannot "re-license" MIT-licensed code, and the MIT-licensed code will remain under the MIT License, but you can redistribute it as part of another project under any license you wish. You should make it clear that any changes that you make to the MIT-licensed code are released under your new license. The MIT License text & copyright notice must still be included with any unmodified MIT-licensed code.
Can I use MIT-licensed code in my GPL-licensed project?
Can I use GPL-licensed code in my MIT-licensed project?
No. The project as a whole must conform to the terms of the GPL license and therefore must be distributed under the terms of that license. Therefore such a project as a whole must be distributed as GPL, but can still contain MIT-licensed software.
If I use MIT-licensed software server-side, do I have to display the copyright notice or disclaimer?
This depends. Having MIT-licensed software work server-side (e.g. as a PHP script) to produce a HTML page is not redistributing the software, unless the program includes itself in its output. Therefore you are not giving the user any sort of license to the original software, nor are you required to do so. This even applies to GPL-licensed software.
However, if you are in any way sharing your server-side software with another party, the terms of the license obviously apply in relation to that distribution. The exception to this would be providing the software to a sub-contractor (e.g. a website hosting company) where you do not grant them any license to redistribute or use the software except as directed by yourself. This also applies to the GPL.
Copyright © <years> <copyright holder>
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 MIT License as approved by the Open Source Initiative
- The Expat License as described by the Free Software Foundation
You can also contact me directly - I make an effort to reply to every e-mail.