Skip to main content

How To Care If BSD, MIT, or GPL Licenses Are Used

The two recent posts about some individuals' choice of GPL versus others' preference for BSD and MIT style licensing has caused a lot of debate and response. I've seen everything as an interesting combination of very important topics being taken far too seriously and far too personally. All involved need to take a few steps back.

For the uninitiated and as a clarifier for the initiated, we're dealing with (basically) three categories of licensing when someone releases software (and/or its code):
  1. Closed Source. Easiest to explain, because you just get nothing.
  2. GPL. If you get the software, you get the source code, you get to change it, and anything you combine it with must be under the same terms.
  3. MIT and BSD. If you get the software, you might get the source code, you get to change it, and you have no obligations about anything else you combine it with.
The situation gets stickier when we look at those combinations and the transitions between them.

Use GPL code with Closed Source code

So long as you don't distribute your software this is fine. It is a perfectly OK thing to do for software running servers or only running in-house. However, if you want to distribute your software to end users, the terms of GPL code require that the GPL also applies to your own code, so you've got to give that code away, rather than keep it closed. Further, you have to let the users modify and redistribute it.

Returning modifications upstream?

Go ahead. As the owner of the closed source, if you decide to take portions that have modified the GPL code and return that to the project as a thank you, it is your right. You don't have to release your entire project's code to do this. Similarly, if you want to release other portions of your code for use, it is likely required to be GPL, itself.

Use MIT/BSD code with Closed Source code

This happens a lot, in the same kind of situation above, but also in distributed software, because that is OK. In some cases, a notice that you use the code is required, but you aren't required to put your own code under any particular rules or license.

Returning modifications upstream?

Just like GPL, this is fine. However, you have more freedom about releasing other components of your code under any license you see fit.

Use GPL code with MIT/BSD code

Oh, no! Now you have a problem, because the release of your own code under MIT and BSD style licensing is forbidden if you include or link it (the terms can be fuzzy with modern runtimes) with GPL code. You probably just can't use any GPL code if your own is MIT/BSD style.

Use MIT/BSD code with GPL code

Sure, go ahead. The GPL is fairly receptive. If you release an application under the GPL and it requires or includes MIT/BSD style licensed libraries, that is just fine.


If you're a closed source, server side or in-house project, you dont' have much to worry about. You aren't distributing, so little of this matters to you. If you're a closed source, distributed product, then GPL is off limits for you. As the lead of an open source project, you still need to worry about GPL code. Either it can limit how people can use your code, by forcing it to become GPL, or you could face limited use by making the decision yourself. In short, while its an acceptable license for its uses, it happens to be most limiting under these factors.

If you release some GPL code, I probably can't use it. Period. End of story (ignoring these commentaries about the story). Now, maybe you don't care if I can't use it, but isn't that why you're releasing it? The GPL is meant to protect us, but who and what does it protect us from? I can't release it in a closed source product, and I don't want to, but you're also keeping honest, open source enthusiastic developers from using your project. You aren't limiting us for technical or legal reasons, but only for our choice of another license. A GPL licensee can say anything about everyone having a freedom to choose their license, and this is true, but you can't escape your own choice specifically limits who else can interoperate based entirely on if they agree with you.


Florian said…
The choice of license is an act of personal believe and convictions.

You postulate that *GPL users are making a flawed moral choice by expecting others to agree with their convictions and that BSD/MIT users are above such flaw.

However, by suggesting that *GPL users agree with your convictions and switch to BSD/MIT, you invalidate any moral ground to make such a claim.

If you are truly committed to impose no choice on others, you may not, ever, make any suggestions that others (even when in fault) change their convictions to suit yours.
rgz said…
Oh no I have to call bu****it.

You can use all the the GPL you want in your distributed code, nothing is stopping you. You just have to change your license from MIT to GPL oh but you wouldn't do that!

You bash GPL users for their choice of license but you are unwilling to change license yourself, you are the one imposing the restriction, but why?

The GPL is meant to protect us, but who and what does it protect us from? I can't release it in a closed source product, and I don't want to, but you're also keeping honest, open source enthusiastic developers from using your project.

Oh no you don't, You want it to go closed source or at least keep it an option. Otherwise you wouldn't have a problem changing your license to GPL.

The the only reason to reject GPL'ed code you want use is because you can't take it into closed source projects.
ivan said…
Do you know if I have a library or framework under the GPL license and someone builds a proprietary software(custom web site) for just 1 customer, and hands over the source code to this customer, can we say he is distributing the framework ? I mean in this situation do I have a right to ask him to publish the source for everyone or to buy a commercial license from me ?
Anonymous said…
@ivan: he's only required to provide the sourcecode to the customer. If you didn't buy, he's not required to (unless the license is AGPL or RPL, this changes the rules).
Anonymous said…

"The the only reason to reject GPL'ed code you want use is because you can't take it into closed source projects."

Yes, god, exactly. That's the whole freaking problem with GPL! I'm not sure what world you are living in, but most of my customers are not interested in giving the source code we right away to the public. Nobody wants to create competitors for themselves.

I'm glad that people out there are interested in writing high quality, free libraries for me to use (I don't really care of they are open source or not; it's the free part that I like). But forcing your software politics down peoples throat is bullshit and that's why GPL is bullshit. If you want to release your source code, go ahead. Forcing others to do it just for the privilege of using your library sucks.

Popular posts from this blog

On Pruning Your Passions

We live in a hobby-rich world. There is no shortage of pastimes to grow a passion for. There is a shortage of one thing: time to indulge those passions. If you're someone who pours your heart into that one thing that makes your life worthwhile, that's a great deal. But, what if you've got no shortage of interests that draw your attention and you realize you will never have the time for all of them?

If I look at all the things I'd love to do with my life as a rose bush I'm tending, I realize that careful pruning is essential for the best outcome. This is a hard lesson to learn, because it can mean cutting beautiful flowers and watching the petals fall to the ground to wither. It has to be done.

I have a full time job that takes a lot of my mental energy. I have a wife and a son and family time is very important in my house. I try to read more, and I want to keep up with new developments in my career, and I'm trying to make time for simple, intentional relaxing t…

The Insidiousness of The Slow Solution

In software development, slow solutions can be worse than no progress at all. I'll even say its usually worse and if you find yourself making slow progress on a problem, consider stopping while you're a head.

Its easy to see why fast progress is better: either you solve the problem or you prove a proposed solution wrong and find a better one. Even a total standstill in pushing forward on a task or a bug or a request can force you to seek out new information or a second opinion.

Slow solutions, on the other hand, is kind of sneaky. Its insidious. Slow solution is related the Sunk Cost Fallacy, but maybe worse. Slow solutions have you constantly dripping more of your time, energy, and hope into a path that's still unproven, constantly digging a hole. Slow solutions are deceptive, because they still do offer real progress. It is hard to justify abandoning it or trying another route, because it is "working", technically.

We tend to romanticize the late night hacking…

Finding "One Game A Month"

I was really excited about the One Game A Month challenge as soon as I heard about it.
For about two years I've struggled in fits and starts to make my way into game development. This hasn't been productive in any of the ways I hoped when I started. Its really difficult to be fairly experienced as a developer, which I believe I am in my day job as a web developer, while struggling really hard at an area in which your experience just doesn't exist.
Its like being a pilot who doesn't know how to drive.

But this challenge provided a new breath to this little hobby of mine. It gave me a scaffolding to experiment, to learn, to reflect on finished projects. I had spent far too much time on game projects that stretched on far past their exciting phases, bogged down by bad decisions and regret.
And it has worked.
I have a lot to learn. I have a lot of experience to gain through trial and error and mistake and discovery. I have a lot of fun to be had making more small games t…