I'm looking at using a few open source products in a commercial software application I'm working on. One of them is licensed under MIT, which I understand as allowing commercial software linking. However, the other open source product is licensed under MS-PL but I don't understand if that license is fully compatible with commercial software.

So the question is, can I use MS-PL licensed OSS in a commercial/proprietary/for-sale application?

  • What is the question?
    – Armando
    Jun 19, 2011 at 16:18
  • @Armando Edited to be clearer Jun 19, 2011 at 16:31
  • There's all varieties of commercial software, including under every Free/Open Source license. You really do need to clarify how you intend to use software. Jun 20, 2011 at 13:54

2 Answers 2


First, a terminology correction, the word you are looking for is "proprietary", not "commercial". Open source software is commercial in every sense of the word. It is created by businesses, sold to businesses, and used by businesses. This is true in practice and was so recognized by the courts in an important legal case.

As for the license you are asking about, go to http://www.opensource.org/licenses/ms-pl.html and read the text. (Note that the license was created by Microsoft for use in software written by Microsoft - which is not known as a charity. That is commercial software.) Reading section 3.D. it is within the rights granted by the license to distribute a compiled binary including that software, however you have to abide by the terms of the software. So, for instance, you can't use the contributor's name, logo, etc for your software. (Odds are that the contributor is Microsoft.) It should be very easy to to comply with that license. But if you are in serious doubt about whether you are complying, consult with a lawyer.

  • 1
    Still doesn't make sense. So what would I have to do to comply in the case where I compile the MS-PL source in a proprietary software component, vs. distribute the MS-PL source as part of a prop software component?
    – Dr. ABT
    Feb 22, 2012 at 20:07
  • At the bottom of the link to opensource.org, there is a comment which asserts that the source "needs to be available". I have read the MS-PL top to bottom about 10 times now. I still cannot find where it says that I need to make the source code of my application publicly available. Is the commenter mistaking, am I reading the comment wrong or am I blind?
    – Tormod
    Feb 8, 2013 at 14:45
  • 2
    @Tormod You're getting confused by a comment that is a bad answer to a confused question. Someone appears to be confusing the MS-PL with the GPL, which does indeed have an availability requirement. I'll raise the issue on the OSI mailing list, and hopefully it gets fixed pretty soon.
    – btilly
    Feb 14, 2013 at 10:13

I wrote about interpreting software licenses a while ago. You might find that helpful.

As I see it, the MS-PL is a fairly simple open/source license. It is OSI-aproved, which makes it compatible with most FOSS licenses, except the GPL, because the GPL is viral and requires availability of source, and the MS-PL is viral if source code is distributed.

  • -1. The OP asked about the MS-PL, not the MPL. Jun 20, 2011 at 1:34

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