Yzena Viral User License

A viral copyleft network license that is readable and thorough and respects user agency.

Yzena Viral User License 0.1

Version 0.1

This license is a draft. Do not use.


This license gives users as much permission to work with this software as possible, while protecting contributors from liability and ensuring that anyone who makes this software part of any software available for public use publishes their changes and the source code of any software combined with this software, as well as ensuring that user agency is respected. It also ensures user freedom to modify this software and to use as such.


In order to receive this license, you must agree to its rules. The rules of this license are both obligations under that agreement and conditions to your license. You must not do anything with this software that triggers a rule that you cannot or will not follow.

Source Code

In this license, the phrase “source code” includes the original copyrighted material of any software.

This Software

In this license, the phrase “this software” includes the source code licensed under this license. It also includes the output of any execution of any algorithm that uses all or part of this software as all or part of its input, but only if the output itself is software.

Combined Software

In this license, the phrase “combined software” means this software alone. It also means any piece of software which results from combining this software with any part of any other software into one piece of software.


In this license, the term “application” means any system that uses any piece of combined software.

User Agency

User agency is the concept that users must have the choice of what the software they use does for them, and that software must never disobey the user or obey any other entity in lieu of obeying the user.

Each contributor licenses you to do everything with this software that would otherwise infringe that contributor’s copyright in it, except anything that would break any rule of this license.


Unless any contributor says otherwise, this software can be relicensed under all later versions of this license.


If you wish to distribute this software as part of any software, you must provide the source code on request and without cost, and you must do so under this license or any of the licenses under Compatibility. However, this rule need not apply to the rest of any software for which this software is only a part, including any parts of the software that this software needs.


You must ensure that everyone who gets a copy of any part of this software from you also gets the text of this license.


If the source code includes a file named CREDITS.md or NOTICE.md, then you must ensure that everyone who gets a copy of any part of this software from you, with or without changes, also gets the verbatim text of that file.


This License does not grant you any rights to the names, trademarks, service marks, or logos of any contributors.


You cannot initiate any patent litigation claiming that this software infringes any patent, directly or indirectly.


You must allow, and make it possible, for anyone to modify this software and use the modified version, including modifying any product that this software is a part of. you may also not use this software as part of an application or product that would prevent anyone from modifying and using any other software.

Respecting User Choice

You cannot use this software as part of, or in support of, any application or product that does not respect user agency and that does anything that does not directly accomplish a task that the end user directly requested the product or application to do. This software must not be used as part of, or in support of, any application or product that is not a faithful and obedient agent for the end user, including as part of any application or product that manipulates the user.

This section does not apply if the applicable law does not allow such applications or products to comply.


If any contributor notifies you in writing that you have not complied with Distribution, Notices, Credits, Trademarks, Litigation, Non-Interference, and/or Respecting User Choice, you can keep your license by taking all practical steps to comply within 30 days after the notice. If you do not do so, your license ends immediately after the 30 days.


Each contributor licenses you to do everything with this software that would otherwise infringe any patent claims they can license or become able to license.


No contributor can revoke this license from you unless you do not follow its rules.

No Liability

As far as the law allows, this software comes as is, without any warranty or condition, and no contributor will be liable to anyone for any damages related to this software or this license, under any kind of legal claim.

Yzena Viral User License Frequently Asked Questions

  1. What is the Yzena Viral User License (YVUL)?

    It is a permissive, viral network copyleft license that prohibits Tivoization and weaponizing software against users.

  2. Is the YVUL viral like the GNU GPL and GNU AGPL?

    No, it’s explicitly not viral. In my opinion, virality is parasitic and has caused people to use closed-source software instead of FOSS alternatives when those alternatives were licensed under the GPL and AGPL.

  3. Who are you? And are you a lawyer?

    I am Gavin D. Howard, founder of Yzena.

    No, I am not a lawyer, but most of this license is taken from the Blue Oak Model License 1.0.0 (BOML), which was written by lawyers.

  4. Why did you choose the BOML to start with?

    See here, here, here, and here. Basically, the BOML is supposed to be a model for how licenses should be.

  5. What is the list of changes you made from the BOML?

    These are the changes I made:

  6. If you mostly copied the BOML, why shouldn’t I just use that one?

    You actually should; if all you need is a typical permissive license, then yes, you should use the BOML.

    However, there are three clauses in the YVUL that are not in the BOML:

    If you need those three things in a license, then the YVUL might work for you. Be sure to consult with your lawyer first.

    In addition, this is also a viral network copyleft license that requires respecting user agency, so if that’s what you need, that is another reason the YVUL might work better for you. Again, be sure to consult with your lawyer first.

    In addition, this is also a viral network copyleft license that prohibits Tivoization and using software under this license to do anything that does not serve end users, so if that’s what you need, that is another reason the YNUL might work better for you. Again, be sure to consult with your lawyer first.

  7. Why do you use such vague language and don’t define some of your terms?

    Because the BOML doesn’t. See more here and here. I decided that if lawyers did it, it should be fine.

  8. Your Credits section doesn’t actually require giving credit.

    No, it doesn’t. But it does require providing the verbatim text of the CREDITS.md or NOTICE.md file, and I assumed that the contributors would add whatever credits they wanted in there.

  9. You also don’t require giving a link to the original project, if someone makes changes and relicenses the code.

    No, but I also assumed that the original contributors would put that information in the CREDITS.md or NOTICE.md, and that text must be provided verbatim.

    That assumption simplified the license, which makes things easier on contributors and users.

  10. Why does the Credits section require that the file be in the Markdown format?

    It made it easier to write the license and will make it easier to comply with the license.

    More concretely, the Apache 2.0 License uses the phrase “NOTICE file.” I decided to avoid that awkward language.

    And while I could have chosen any file format, Markdown is text, easily readable, well-supported (with ways to convert it), and should have all of the features that would be needed for such a file.

  11. The Credits section says that it is required to provide the verbatim text of the CREDITS.md or NOTICE.md file. Why didn’t you just require people to provide the file?

    Because if someone makes changes to the software, I wanted them to be able to add their own credits to the CREDITS.md or NOTICE.md file, which they can do by adding theirs at the bottom or the top of the original, since the verbatim text of the original will still be intact.

  12. What do you suggest putting in the CREDITS.md or NOTICE.md file?

    I suggest adding these things:

    • The name of the original software.
    • The original copyrights on the software.
    • A link to the original code/repository.
    • A link to the Yzena Viral User License to inform users that it is possible to get the original under this license if they wish.
    • The (preferred) names of all contributors that want credit.

    I also suggest having a paragraph that says:

    All files in this repository are under the Yzena Viral User License, Version 0.1, and all such files are considered part of the “source code” as defined by that license.

    In addition, if there are files in the repository that used to be under any licenses other than the YVUL, then I suggest listing all such files, along with their respective former licenses and copyrights, as required by their former licenses, but to also make clear that the files have been relicensed.

  13. The previous question implies that everything in a repository should be under the YVUL. What if there is code that is under other licenses?

    Such code should be relicensed, if possible. This is possible with permissive licenses.

    If it is not possible, then such code should not be integrated into the repository.

  14. Does this mean that any code under the GPL family of licenses should not be integrated into a repository under the YVUL?


  15. Why do you care about patents and trademarks?

    Because I want to be able to make a business based on Open Source software, and I do not want to have to worry about losing trademarks or possibly getting sued for patent infringement.

    Also, software patents are, in my opinion, illegal because you can’t patent algorithms. They have also never been used for actual innovation, which makes them useless.

  16. Why did you not use a sunset clause, like copyleft-next? That seems like a good idea.

    It is a good idea, since the term of copyright is much longer than it should be.

    However, unlike movies or other works of art, software is constantly changing. So if there was such a sunset clause in YVUL, it might be ambiguous whether or not the clause applies to all of the software, or just those portions that have existed as long as the sunset term.

    Instead, I opted to keep the BOML’s Reliability clause, which should serve the same purpose.

  17. Why did you not use a nullification of copyright clause, like copyleft-next, to prevent proprietary dual licensing?

    While that clause is also a good idea, its purpose is also somewhat fulfilled by the Reliability clause.

  18. Why did you use the vague phrase “make…this software…part of any application that is available for public use”?

    I intentionally wanted to make the requirement for sharing source kick in for every public use of the YVUL-licensed software, whether direct or indirect. I want code to be shared, first and foremost.

    Obviously, if a company makes a public-facing webapp that uses YVUL-licensed software, that is making it available for public use, and they should be expected to share their changes, if any.

    However, if YVUL-licensed software is used only as part of private infrastructure, there is no expectation to share changes.

    Also, this definition has some other good side effects: it includes software used on things like arcade machines and software included on OEM machines as well, among other things.

    Yes, if YVUL-licensed software is used in an arcade machine available in a public arcade, that is covered under this definition, as is any software that comes preinstalled on computers or phones sold by manufacturers.

    In essence, the reason is that this is a tiny change from the “available to the public” phrase used in the GPL (which already covers software distributed with devices) that should cover the SaaS loophole.

  19. Where do you draw the line “part of an application available for public use”?

    My line is best illustrated with an example.

    Say I write database software and license it under the YVUL. If a company makes a publically available webapp that stores data in my database, even if that database also holds data for their non-public monitoring system, I would consider that the database is part of the publically available webapp, and they should share changes.

    However, if the company does not use my database to store data for the webapp, but only uses it to store data for their non-public monitoring systems, then that would not be part of the publically available webapp, and they do not need to share changes.

  20. What’s with the weird definition for “this software”?

    GitHub Copilot. I want the YVUL to poison the well for machine learning like that.

    The reason is that GitHub is arguing that using FOSS code in Copilot is fair use because using data for training a machine learning algorithm has been labelled as fair use.

    However, even though the training is supposedly fair use, that doesn’t mean that the distribution of the output of such algorithms is fair use.

    The definition of “this software” is crafted to exploit this discrepancy.

  21. But maybe the output of the algorithm is under fair use as well.

    If it is, then copyright disappears entirely from software. The reason for this is that we already use algorithms to transform our software. We call those algorithms “compilers,” and their output “executables” or “libraries.” No one claims that a source code’s copyright does not apply to the binary forms output by a compiler.

  22. What if the output of a machine learning algorithm is transformative? Would that not be enough to defeat copyright?

    A compiler’s output is also transformative, especially if it does optimizations. This especially applies if the compiler is doing link-time optimization using inlining with code from different sources. In that situation, a compiler is combining multiple sources in non-obvious ways, just as machine learning models do.

    A compiler can even transform an O(n) algorithm into an O(1) algorithm!

    In other words, unless GitHub Copilot wants to throw out copyright on software completely, this license will apply to the output of its model.

  23. Why didn’t you just add a clause protecting the output of machine learning?

    I think the definition is wonderfully broad in a way that is best for end users, which is my central purpose: to serve end users who are hurt most by proprietary software.

    In addition, I don’t know what sorts of things will be done to software in the future, and I want to future-proof this license as much as possible.

  24. Your extra restrictions make your license incompatible with the GPL and AGPL.

    I don’t think so.

    First, they are not extra restrictions; they codify something that I believe already exists in the GPL and friends.

    Second, even if they are extra restrictions (which would make this license incompatible with the GPL), I think I am okay with that.

    In fact, if my licenses are not compatible with the GPL and friends, then I will keep the terms I have and accept the incompatibility. I can do this because these licenses will mostly be used for code in a new language, which means that I wouldn’t be able to use existing code easily anyway.

  25. Your extra restrictions make your license non-Open Source.

    Once again, I don’t think so, and for why, see above. The new parts are not new restrictions; they are clarified.

    But even if the license is non-Open Source, I’m not sure I care.

    The reason is this: I believe FOSS licenses have failed. We have so many companies that have used the freedoms we have tried to give users in order to extract value (data or something else) unethically from those very users. They do this by claiming the rights of distribution that the FOSS licenses give them and then using those rights to distribute Open Source software to users in such a way that they don’t realize that they are being taken advantage of.

    The more I’ve understood that, the more I have come to realize that the current iteration of FOSS licenses do not work.

  26. But what will work?

    Remember how I said that companies claim the rights of distribution we give them? As it turns out, end users, so-called because they are at the end of a chain of distribution, don’t usually use distribution rights.

    That means that the next generation of FOSS licenses can probably more heavily restrict how licensed software is distributed while allowing for no restrictions on the other two freedoms of the four freedoms.

    I’m not ready to go that far yet. If I was, I’d add a clause forbidding ads in the software. But that is probably the sort of direction we need to go.

  27. Your license is actually viral, since it makes the license apply to the full output of algorithms.

    I carefully defined “source code” to ensure that was not the case.

    You see, while the license does apply to the entire output, the requirement is still to provide only the source code of the original. There is no requirement to provide the source code of the entire combined software.

  28. Why did you say that “this software” only includes output of algorithms that is itself software?

    Technically, you can run software through things like hash functions, which are algorithms, and the output is entirely unusable as software. Saying that the license would apply to output like that would never work.

    The same goes for static analysis tools. They don’t usually output something that can be considered “software”; instead, they output a list of problems with the software. I wouldn’t want that to be affected by this license.

    In other words, that little part of the definition is required from making the definition so broad that it becomes useless.

  29. Your definition of “this software” has “this software” in the definition.

    That’s because the definition is recursive. The base case is the source code of the software, and then whenever the source code, or the result of transforming “this software” is transformed by an algorithm, the definition recursively applies.

  30. Why did you define “source code”?

    In order to make this license non-viral and because of the recursive definition of “this software”. See the previous question.

  31. What is user agency?

    User agency is a principle that I believe software and programmers should abide by. It is that software should obey its user, and no one else.

  32. Your User Agency and Respecting User Choice sections are vague.

    Yes, that is a limitation, for now. Once I get a lawyer to help me, those sections will be improved.

  33. What did you intend to do with the User Agency and Respecting User Choice sections?

    I intended to make such software unusable in anything, software or otherwise, that would harm users. This includes things like:

    • Implementing backdoored cryptography so that the users’ privacy is invaded.
    • Collecting users’ data without consent.
    • Selling users’ data without consent.
    • Presenting ads to the user from an OS that they paid for.
    • Rent-seeking by making the user pay extra to use something they already own in the way that they want.
    • Using remote attestation, or other techniques, to prevent certain user actions.

    And many more.

  34. What is the purpose of the prohibition on manipulating users in the Respecting User Choice section?

    That prohibition is meant to close a loophole where software might manipulate users to get the users to “request” actions that the software creator wants to happen. This includes things like:

    • Making questions to the user confusing, making it easy to click the wrong item.
    • Adding excessive friction to stop users from requesting actions that the software creator does not want.
    • Nagging the user to accept something.
    • Making the user opt-out, rather than opt-in.

    And many more.

  35. What if someone needs to use software under this license to do something against user agency because of the laws of a country they are in?

    That is allowed, but reluctantly.

    A blanket prohibition would probably not accomplish anything because those who would violate user agency, usually governments, would not care about my license, and having a blanket prohibition would probably prevent developers who use this license from distributing their software in such places. And if software can’t be distributed in such places, it can’t be used by regular people in such places.

    Thus, if this license did not have that exception, then regular people in such places would probably not be able to use software under this license.

    In the interest of allowing regular people to use software under this license, I have this exception.

  36. Why did you write this FAQ when nobody has asked you any questions yet?

    To establish intent. If these licenses have to be tested in court, then if my intent is clear, that can help judges and juries resolve ambiguities and decide if a license violation happened.

    The GPL and AGPL did the same thing. However, in those cases, the licenses include the intent in the preambles to the licenses, which muddies the waters. The reason for this is because if the preamble conflicts with another part of the license, which part wins?

    To stop that from happening, I set forth my intent in this FAQ, but I also explicitly made it a separate document (in the repository). That way, if the FAQ conflicts with the license, the license wins hands down.