Main question

Is 0BSD actually a valid license for work in the public domain? Would it cause problems in some jurisdictions? Is there a better option to publish US-public-domain uncopyrightable code so that people can just use it?


I work for the U.S. Government and sometimes develop software that I want to release open-source. This is totally allowed by my employer and even mildly encouraged.

The crucial question is, which license should I use? My goal is simple: allow the greatest number of others to be able to use my code, with the least amount of hassle.

The complication comes because U.S. Government work product is not copyrightable as it is in the public domain. In the past I have used the Unlicense as a kind of beefed-up public domain declaration. But since then I have learned that there are various problems with public-domain declarations and the Unlicense in particular. In summary, public domain only applies in the U.S. and doesn't even make sense in other countries such as Germany, and (as a result) some companies have a blanket policy to not use code released under Unlicense or WTFPL.

I recently discovered the 0BSD license, which is considered "public-domain equivalent", is allowed by companies such as Google, and (unlike CC0) is listed by the Open Source Initiative. Note that the 0BSD text linked here does not include any copyright statement.

Additional reading

The helpful reader may be tempted to suggest I ask my employer what to do. If you are familiar with government work, you should not be surprised to discover that (1) there is an extensive document and even an FAQ which both fail to answer my question, and (2) my local agency was unable to provide any further clarification and was annoyed that I asked.

  • The FAQ you linked has an entry “Can government employees develop software and release it under an open source license?”. It says that copyright-based licenses cannot be used, and that public domain is the absence of copyright. Despite not requiring a copyright notice, I'd consider 0BSD to be copyright-based. Note that CC0 is an excellent tool, it just wasn't OSI-approved because it explicitly withholds patent licenses.
    – amon
    Commented Feb 6, 2021 at 20:27
  • @amon "Despite not requiring a copyright notice, I'd consider 0BSD to be copyright-based" - can you explain this claim?
    – Dan R
    Commented Feb 7, 2021 at 18:49
  • The 0BSD license grants certain permissions. Under which authority are these permissions granted? If the software were public domain, the author would not have the right to withhold or grant these permissions. Only because the licensor does hold the copyright can they grant these permissions. Other licenses also use patent rights, trademarks, and contract law as the source of their effectiveness/enforceability. The author holds copyright regardless of whether the copyright was registered or a copyright notice was affixed to the program.
    – amon
    Commented Feb 7, 2021 at 19:16
  • @amon So it seems fine to me then - in jurisdictions that honor the public domain declaration, the "grant" is irrelevant as such rights have already been granted, and in other jurisdictions the grant is valid. Either way, the rights listed in 0BSD would hold up, yes?
    – Dan R
    Commented Feb 7, 2021 at 20:29

1 Answer 1


Is 0BSD actually a valid license for work in the public domain?

Technically not, because you are trying to give a copyright license on something that isn't protected by copyright law.

Would it cause problems in some jurisdictions?

I am no lawyer, but I can see it causing issues in the US if someone takes issue with the fact that a public-domain work carries a copyright license.

Is there a better option to publish US-public-domain uncopyrightable code so that people can just use it?

I would give the work a "dual license" along the lines of

"This work is produced on behalf of the US government and is hence in the public domain. If such a public domain work is not recognized in your jurisdiction, you can consider it to be licensed under the following license: <0BSD license text>".

This makes it clear the work is intended to be in the public domain, and gives a very permissive license for those cases where public domain doesn't work.

  • 1
    Mind that the BSD0 explicityl does NOT carry a copyright statement. Commented Feb 3, 2021 at 6:40
  • @planetmaker, under the Berne Convention, the copyright statement is at best an informative piece of text. Commented Feb 3, 2021 at 6:46
  • @BartvanIngenSchenau USA law is conflicting at this with Berne: en.m.wikipedia.org/wiki/Copyright_notice - some discusion.
    – gavenkoa
    Commented Feb 6, 2021 at 20:53
  • @planetmaker It seems like there are different versions of the 0BSD license. The OSI version has no copyright statement, but the ones on choosealicense.com and Wikipedia do. Commented May 4 at 0:41

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