[License-review] Adding the curl License

Wed Feb 4 18:44:36 UTC 2026

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). 
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/).

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).

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, <daniel at haxx.se> 
<mailto: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, <daniel at haxx.se>
The permission for listing by the Open Source Initiative can be found 
here: 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

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

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

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 Softwarewithout restriction, including 
without limitation the rights to use, copy, modify, merge, publish, and 
distribute, sublicense, and/or sell copies of the this sSoftware, and to 
permit persons to whom the Softwareis furnished to do so, subject to the 
following conditions:for any purpose with or without fee is hereby 
granted, provided that

tThe above copyright notice and this permission notice appear(including 
the next paragraph)shall be included in all copiesor 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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