I'm developing a Javascript library, and I'm thinking about releasing it under an open source license (e.g. GPL, BSD, MIT) — but that requires that websites that use the software link back to my website.

Do you know about any such licenses? And how have they formulated the attribution part of the license text?

Do you think this BSD-license would do what you think that I want? (I suppose it doesn't :-))

[...] 3. Each website that redistributes this work must include a visible rel=follow link to my-website.example.com, reachable via rel=follow links from each page where the software is being redistributed.
(For example, you could have a link back to your homepage, and from your homepage to an About-Us section, which could link to a Credits section)

I realize that some companies wouldn't want to use the library because of legal issues with interpreting non-standard licenses (have a look at this answer: https://softwareengineering.stackexchange.com/a/156859/54906). — After half a year, or perhaps some years, I license the work under plain GPL + MIT too (in addition to the original license).

  • Well, the answer you linked basically says that "Notification is onerous." It doesn't assert that non-standard licenses are risky, per se. Dec 19, 2012 at 3:15
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    @RobertHarvey I was thinking about this paragraph: "Unless you have legal training, you should not attempt to invent your own licenses. You may think you know what those words mean, but when interpreted by a law court, they may mean something different to what you intend them to. And the licensee of your software would have the same problem. They would have to talk to their lawyers to get an opinion on what the license would mean for them and their businesses." (programmers.stackexchange.com/a/156859/54906 )
    – KajMagnus
    Dec 19, 2012 at 3:19
  • The only problem that I can see is how you would enforce your additional condition. But adding the clause to an existing license as an additional term/condition doesn't seem all that difficult or risky. Except, of course, with respect to the "onerous nature of notification." Dec 19, 2012 at 3:21
  • @RobertHarvey Can it not be argued about the GLP too, that I wouldn't be able to enforce the requirements therein? (Or perhaps the FSF would help, or would they be too busy)
    – KajMagnus
    Dec 19, 2012 at 7:04
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    Keep in mind that many can-we-use-this decisions boild down to "Does it use one of those 4 well-known licenses without any modification?" And no matter how open, well-intended or non-onerous your license is: it will fail that test. Dec 19, 2012 at 14:51

1 Answer 1


Yes, you can create a license that says that. No, you shouldn't do it.

First, what's the point? If you're trying to get attribution for your work, there are a number of licenses that already require that. Creative Commons has a number of licenses that should fit the bill.

Requiring a link-back is dubious at best. There's no guarantee you'll get any extra traffic, and how would you enforce that sort of a request? More importantly, why would you impose an annoying restriction upon the future users of your product? You're just scaring them away.

Trying to game search engines with a link back is also a dubious endeavor. Just because you think the engines work a particular way now doesn't mean that they will continue to work that way in the future. My third point below really focuses on this aspect. Search engines are amongst the most rapidly changing technologies.

Second, why are you even considering changing the license structure at a later point in time? Again, what's your point? Pick the license or licenses that meets / meet your aims and stick with it. Changing the license structure is a great way to annoy and scare off your existing user base as well as scaring away future users. The future users will say "he did this once, what's to keep him from doing it again?"

Changing a license may mean nothing to you, but for organizations using your product it means more work. The new license has to be reviewed; it may not mesh with their legal requirements; it may force them to pick a new product to provide the same function. Don't do it unless you really have to.

Moving to a dual license structure later on doesn't bypass any of that additional work that you're creating for your users as you don't necessarily know which categories they're going to fall into. *They* have the potential liability, so *they* are the ones who have to perform the review.

You mentioned selective enforcement of the license in one of your comments, and you might be considering that as a way of avoiding some of the problems brought up by this second point. However, selective enforcement is tantamount to discrimination. In some jurisdictions it will be tolerated, but in other jurisdictions you'll lose all rights to enforcement. If you put a non-enforcement clause in writing then you're merely compounding the issue by creating confusion about what the terms of the license truly are.

Third, your suggested phrasing of the change is brittle. Specifying a technology or implementation in something that it supposed to outlast various technologies is a bad idea. How would people comply in the future if the requirement is technically infeasible? The answer is they won't and that means they won't use your product either.

If you want to gain traction with your product manipulating the license (or search engines) is not the way to do it. The best way to gain traction is to simply write a great product. Make it available; show how great it is; keep the support active; and it will grow.

If you're worried about a competitor copying your source then don't release the source. Ever. License and Copyright only protect you if you can prove that those aspects were violated. Proving the violation can be amazingly difficult to do. All of the machinations you've suggested merely make it harder for legitimate users to use your product and do very little to keep future competitors from stealing your product. By definition, criminals don't obey the law.

  • Concerning releasing under another license — changing the license wasn't the point, making the software more free was the intention. So I just edited the original post to read: "After half a year, or perhaps some years, I license the work under plain GPL + MIT too (in addition to the original license)".
    – KajMagnus
    Dec 19, 2012 at 15:05
  • Concerning backlinks. Extra traffic directly via those links wasn't really the intention — what I had in mind, was search engines.
    – KajMagnus
    Dec 19, 2012 at 15:09
  • there are valid reasons to want to dual license things
    – jk.
    Dec 19, 2012 at 15:09
  • The point with the license is (from my point of view) that it wouldn't feel great if some competitor copies the software and builds a competing product, without at least linking back to my website. — It wouldn't feel great right now, when I'm building the software and just getting started. However, after a while, when I'm "up and running" (if that ever happens), it doesn't matter much what other people/companies do, and I suppose I'd be happy with licensing under MIT as well.
    – KajMagnus
    Dec 19, 2012 at 15:13
  • @jk - that's a good point, and I wasn't trying to suggest that dual licensing is bad. Changing the license is what throws people off. I'll edit to reflect that.
    – user53019
    Dec 19, 2012 at 15:16

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