[License-review] Adding the curl License

Thu Feb 5 09:51:26 UTC 2026

If it was a new license, I would advise to non-accept it. But since it's a widely used and for a long time license, I think we can give it a slot in the accepted licenses list, since any proliferation concerns are moot at this point ;-) 

Carlo 

Da: "Christoph Röth via License-review" <license-review at lists.opensource.org> 
A: "license-review at lists.opensource.org" <license-review at lists.opensource.org> 
Cc: "Christoph Röth" <Christoph.Roeth at web.de> 
Inviato: Mercoledì, 4 febbraio 2026 19:44:36 
Oggetto: [License-review] Adding the curl License 

BQ_BEGIN

Dear OSI License-Approval Forum, 

I would like the curl license to be added. The license has been around for quite some time, so it can be classified as a legacy license. The license is available at SPDX. The first communication with the OSI took place in the license-discuss forum ( [ https://lists.opensource.org/pipermail/license-discuss_lists.opensource.org/2026-January/022507.html | https://lists.opensource.org/pipermail/license-discuss_lists.opensource.org/2026-January/022507.html ] ). I have received permission from the author of the curl project to have the license listed with OSI ( [ https://curl.se/mail/lib-2026-02/ | https://curl.se/mail/lib-2026-02/ ] ). 

The question was raised in the discussion forum whether there are plans to convert the Curl license to MIT. Since the license has been in use for over 20 years now, there are no plans to change it. The reasons for this are listed in the email communication. 
In my opinion, the separate listing at SPDX also speaks in favour of a separate license ( [ https://spdx.org/licenses/curl.html | https://spdx.org/licenses/curl.html ] ). 

Please find enclosed the information required for submitting a license to the license-review mailing list. 

**• Submit a copy of the license as an attachment in simple text format.** 

COPYRIGHT AND PERMISSION NOTICE 

Copyright (c) 1996 - 2015, Daniel Stenberg, [ mailto:daniel at haxx.se | <daniel at haxx.se> ] . 
All rights reserved. 

Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. 

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 

Except as contained in this notice, the name of a copyright holder shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization of the copyright holder. 

**• Affirmatively state that the license complies with the Open Source Definition, including specifically affirming it meets OSD 3, 5, 6 and 9.** 

I can confirm that the license complies with the Open Source Definition. 

3. Derived Works: Yes 

5. No Discrimination Against Persons or Groups: Yes 

6. No Discrimination Against Fields of Endeavor: Yes 

9. License Must Not Restrict Other Software: Yes 

**• Identify what projects are already using the license.** 

The curl project itself. 

**• Provide the identity and contact details of the license steward, if known, and of the submitter. The OSI will try to get in touch with the license steward if the license submitter is not the steward.** 

Daniel Stenberg, < [ mailto:daniel at haxx.se | daniel at haxx.se ] > 
The permission for listing by the Open Source Initiative can be found here: [ https://curl.se/mail/lib-2026-02/ | https://curl.se/mail/lib-2026-02/ ] 

**• Provide any additional information that the submitter believes would be helpful for license review. For example, approval of the license by Debian, the FSF or the Fedora Project would be relevant to the review process.** 

The website contains this text with detailed information about the license, [ https://curl.se/docs/faq.html#license | https://curl.se/docs/faq.html#license ] 

What license does curl use exactly? 

curl is released under an MIT derivative license. It is similar but not identical to the MIT license. 

The difference is considered big enough to make SPDX list it under its own identifier: curl. 

The changes done to the license that make it uniquely curl were tiny and well-intended, but the reasons for them have been forgotten and we strongly discourage others from doing the same thing. 

**• Provide a unique name for the license, preferably including the version number.** 

Full name: curl License (according to SPDX) 

Short identifier: curl (according to SPDX) 

**• If any exist, provide the unique identifier by other projects, like SPDX or ScanCode.** 

[ https://spdx.org/licenses/curl.html | https://spdx.org/licenses/curl.html ] 

McCoy Smith added a comparison of the licenses to the License-discuss forum. Here is the content of the *.odt file that was attached at the time. The colours blue and red are the colours used in SPDX. The strikethrough text was included in the MIT license and has been omitted from the curl license. The green text was not available in the MIT license and has been added. I hope the email transfers the format correctly. 

MIT License 

COPYRIGHT AND PERMISSION NOTICE 

Copyright (c) < year> <copyright holders> 1996 - 2015, Daniel Stenberg, [ mailto:daniel at haxx.se | <daniel at haxx.se> ] . 
All rights reserved. 

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the " Software "), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, and distribute , sublicense, and/or sell copies of the this s S oftware , and to permit persons to whom the Software is furnished to do so, subject to the following conditions: for any purpose with or without fee is hereby granted, provided that 

t T he above copyright notice and this permission notice appear (including the next paragraph) shall be included in all copies or substantial portions of the Software . 

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS . IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE . 

Except as contained in this notice, the name of a copyright holder shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization of the copyright holder. 

Best regards 

Christoph 

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BQ_END

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