quick question, i'm doing research into open source software and i was wondering if open source software be proprietary? if so, what examples exist? what examples exist of source code that is open source but also proprietary?

how would that work? how would the source code be available but the program also be proprietary? wouldn't the users just take the source code and compile the program themselves as opposed to paying for it? thank you

  • 5
    What do you mean by open source but proprietary? Do you mean "the source is available but you're not allowed to study/share/modify it"?
    – MadHatter
    Jun 15, 2021 at 15:33

1 Answer 1


First let's establish what is meant when we talk about open source code.

Code that is published without any license attached to it, is open but proprietary. The copyright of that code belongs to the developer who wrote it. You need to obtain permission from the author to use it.

This author can release that code under a license. If that license is approved by the Open Source Initiative (OSI) then that code isn't only open, it's also open source.

Code that is open source can't be proprietary. The original author still had the coyright (that's inalienable in many jurisdictions), but with the open source license the author grants at least 10 rights (defined by OSI) to everyone who obtains a copy of the source code.

Among those rights are the irrevocable freedom to use, to redistribute, to create derived works, and so on.

There is proprietary code that is distributed along with the binaries under a different license (e.g. the Business Source license used by MariaDB for clustering databases), but although that code is open, it isn't open source because the Business License wasn't approved by OSI.

  • 1
    To "code published without a license" you have the default rights, i.e., none whatsoever. Not reading, not studying, not using. Period. If you look closely, if it is published on some site, the site states that the publisher gives some rights by publishing on it (e.g. check the conditions on github or StackOverflow). I'd steer well away from such code, it could bring untold grief later on.
    – vonbrand
    Jun 20, 2021 at 2:51
  • Indeed, that's what I meant when I wrote that it's proprietary. You need permission from the author to use it. I would also stay away from it unless there are clear rules about using it (e.g. based on the terms & conditions of the website of the publisher). It is also very important to document these conditions, because a publisher can change them. Make sure the rights you received are irrevocable, as is the case with (AFAIK all) open source licenses. Jun 20, 2021 at 7:23
  • @vonbrand If you have a legit copy of a copyright work, you have the right to read it and study it. Almost every book sold is without license, and just the default rights.
    – prosfilaes
    Jul 9, 2022 at 0:57

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