Permissions, conditions and limitations at a glance
Conditions
- None
Limitations
- LiabilityExpressly states that there is no liability for damages.
- WarrantyExpressly states that no warranty is provided.
Permissions, conditions and limitations are classified using data from choosealicense.com (GitHub, MIT License).
What kind of license is it?
The Unlicense is a public domain dedication published around 2010. It opens with the declaration "This is free and unencumbered software released into the public domain" and states that anyone may copy, modify, publish, use, sell or distribute it, in source or binary form, for any purpose. In jurisdictions that recognize copyright laws, the author dedicates any and all copyright interest to the public domain, and it ends with a warranty disclaimer. youtube-dl and its successor yt-dlp use the Unlicense. The Unlicense is an OSI-approved open source license (according to the SPDX list).
Conditions
None. There is no notice requirement either.
Limitations and criticism
- Some countries (e.g. civil law jurisdictions such as Germany) consider it legally difficult for authors to fully give up their copyright. The Unlicense includes a sentence to address this, but it has been criticized for not having a systematic fallback license clause like CC0.
- Its wording is relatively informal, so conservative corporate legal teams sometimes hesitate to contribute to or use it.
- It does not mention patents.
Common misconceptions
- "The Unlicense is the same as having no license" — It is the opposite. Code without a license has all rights reserved, while the Unlicense is an affirmative declaration giving up all rights.
- "Putting someone else's MIT code into an Unlicense project makes it public domain" — Only the copyright holder can give up rights. The imported MIT part continues to follow MIT terms (keeping the notice).
How to apply it
Put the text in a LICENSE or UNLICENSE file. There is no place to write a copyright holder's name. The SPDX identifier is Unlicense.
When it fits
Use it when you have no intention of exercising copyright and want to release code with as few conditions as possible. If you want more legal certainty, CC0 or 0BSD are alternatives.
Can Unlicense code go into another project?
General verdicts for taking code released under this license and distributing it combined into a project under each license below. See other combinations in the compatibility checker →
| Target project | Verdict | Notes |
|---|---|---|
| Proprietary (closed-source) software | Allowed | This license has no notice requirement, so the code can go anywhere. |
| MIT | Allowed | This license has no notice requirement, so the code can go anywhere. |
| Apache-2.0 | Allowed | This license has no notice requirement, so the code can go anywhere. |
| MPL-2.0 | Allowed | This license has no notice requirement, so the code can go anywhere. |
| LGPL-2.1 | Allowed | This license has no notice requirement, so the code can go anywhere. |
| LGPL-3.0 | Allowed | This license has no notice requirement, so the code can go anywhere. |
| GPL-2.0 | Allowed | This license has no notice requirement, so the code can go anywhere. |
| GPL-3.0 | Allowed | This license has no notice requirement, so the code can go anywhere. |
| AGPL-3.0 | Allowed | This license has no notice requirement, so the code can go anywhere. |
The content on this site is general information, not legal advice. For actual distribution, contracts or disputes, consult a lawyer or other qualified professional.