Content License Guide

Synapse · SYN-LEGAL-LICENSES-2026-09 · Last updated: 19 September 2026

Every public project, problem and post on Synapse should say what other people may do with it. This guide explains the license types offered and contains the full text of each.

1. How licensing works on Synapse

Publishing does not give Synapse ownership of your work. It only hosts it under the terms you attach.
Viewing on the site is allowed. Download, fork, commercial use and modification follow the license text, not the card summary.
Custom and proprietary licenses are only as strong as the terms you write. Empty custom terms mean no license is granted.
These drafts are starting points, not legal advice. If the work is valuable, consult a lawyer in your country.

2. License families

Keep the work closed

No license attached

No license is an explicit choice that you are not offering a grant. People may view the post. They do not get permission to copy or reuse the work unless the law already allows it or you grant rights later. It is not the same label as All Rights Reserved, but reuse is still not granted.

Permissive open licenses

MIT, Apache 2.0, and BSD 2-Clause. Others may use, change, and ship the work, including commercially, if they keep the copyright notice and any extra conditions (Apache also grants patents and asks you to mark changes).

Copyleft and share-alike

GNU GPL v3 and CC BY-SA 4.0. Others may build on the work, but what they distribute must stay under the same family of terms.

Creative Commons for media and writing

CC BY, CC BY-SA, CC BY-NC, and CC0. These fit images, docs, and datasets better than software. CC BY-NC forbids commercial reuse. CC0 waives copyright as far as the law allows.

3. At a glance

Type	Copy & use	Commercial use	Credit required	Share-alike
All Rights Reserved / none	Only with permission	Only with permission	n/a	n/a
MIT, BSD-2-Clause	Yes	Yes	Keep notice	No
Apache-2.0	Yes, with patent grant	Yes	Keep notice, state changes	No
GNU GPL v3	Yes	Yes	Keep notice	Yes
CC BY 4.0	Yes	Yes	Yes	No
CC BY-SA 4.0	Yes	Yes	Yes	Yes
CC BY-NC 4.0	Yes	No	Yes	No
CC0	Yes	Yes	No	No

4. Choosing well

Software you want people to adopt: MIT or Apache-2.0 (choose Apache-2.0 if patents matter).
Software that must stay open: GNU GPL v3.
Art, writing, datasets and 3D models: a Creative Commons license (avoid CC licenses for software).
A business you plan to sell: keep All Rights Reserved and grant permission case by case.
Code you did not write entirely: you can only license what you own; keep third-party code under its own license.
Employer or client work: check your contract, they may own it.
Open licenses are hard to take back: recipients keep their rights if you later change the license.

5. All Rights Reserved (UNLICENSED)

You keep every right. Others may view the work on Synapse but may not copy, modify, distribute, or use it — including commercially — without your explicit written permission.

What this allows

You keep full copyright and all related rights.
Viewing on Synapse is allowed; reuse is not.
Any copy, modification, or commercial use needs your written permission.

Full license text

ALL RIGHTS RESERVED

Copyright (c) [year] [copyright holder].

All rights in this work are reserved by the copyright holder.

Except for viewing this work on the platform where it was published, no person may copy, reproduce, distribute, publicly display, modify, adapt, translate, create derivative works from, sublicense, or commercially exploit this work, in whole or in part, in any medium, without the prior written permission of the copyright holder.

This notice does not grant any implied license. Any permission granted in writing is limited to the scope stated in that writing and may be revoked if those terms are breached.

THE WORK IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED. THE COPYRIGHT HOLDER SHALL NOT BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY ARISING FROM THE WORK.

6. No license (NOASSERTION)

You are not attaching a license. People may view the post on Synapse. They do not get permission to copy, modify, ship, or use the work unless the law already allows it (for example fair use) or you later grant rights in writing.

What this allows

No license is granted by this post.
Viewing on Synapse is allowed.
Reuse, copies, and commercial use are not permitted unless you grant them separately.
You can switch to All Rights Reserved or an open license later.

Full license text

NO LICENSE

Copyright (c) [year] [copyright holder].

The author has not offered a license for this work.

Publication on this platform lets others view the work there. It does not grant a copyright license to copy, modify, distribute, publicly perform, sublicense, or commercially exploit the work.

If you want to use this work beyond viewing it on the platform, contact the author and obtain permission in writing. Until a license is attached, treat the work as unlicensed.

This notice is not legal advice and does not waive any rights the author may have.

THE WORK IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND.

7. MIT License (MIT)

A short permissive license. Anyone may use, copy, modify, merge, publish, and sell the work, including commercially, if they keep the copyright notice and license text. Provided as-is, with no warranty.

What this allows

Commercial use, modification, distribution, and private use are allowed.
The copyright notice and this license must be kept in copies.
No warranty or liability is accepted by the author.

Full license text

MIT License

Copyright (c) [year] [copyright holder]

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, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice 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. 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.

8. GNU GPL v3 (GPL-3.0-only)

Strong copyleft. Anyone may run, study, share, and change the work, including commercially, but distributed modifications must also be licensed under GPL v3 and the corresponding source must be offered. Official text: https://www.gnu.org/licenses/gpl-3.0.html

What this allows

You may run, study, share, and change the work.
Distributed derivatives must be licensed under GPL v3.
Corresponding source must be offered with binaries.
No additional restrictions may be imposed.

Full license text

GNU GENERAL PUBLIC LICENSE
Version 3, 29 June 2007

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 3.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see <https://www.gnu.org/licenses/>.

Summary of the freedoms and conditions (the official legal code is the GNU GPL v3 published by the Free Software Foundation):

0. Definitions. "The Program" is this work. "Covered work" means the Program or a work based on it. "Corresponding Source" is the source needed to generate, install, and run the object code and to modify the work.

1. Basic permissions. You may run the unmodified Program. You may make, run, and propagate covered works that you do not convey, without conditions, as long as your license remains in force.

2. Conveying verbatim copies. You may convey verbatim copies of the Program's source, in any medium, provided you conspicuously publish an appropriate copyright notice, keep intact license and warranty notices, and give all recipients a copy of this License along with the Program.

3. Conveying modified versions. You may convey a work based on the Program under section 2, provided the work carries prominent notices that you modified it and the date, that it is released under this License, and the entire work is licensed as a whole under this License to anyone who comes into possession of a copy.

4. Conveying non-source forms. You may convey a covered work in object code form if you also convey the machine-readable Corresponding Source under the terms of this License, in one of the ways required by GPL v3 section 6 (accompany the source, offer it in writing for at least three years, or use a network server).

5. Additional terms and patents. You may not impose further restrictions. Each contributor grants a non-exclusive, worldwide, royalty-free patent license for essential patent claims to make, use, sell, offer for sale, import, and otherwise run, modify, and propagate the contents of its contributor version.

6. Termination. Any attempt to copy, modify, sublicense, or convey other than as expressly provided voids your rights. Licenses of downstream recipients are not terminated if they remain in compliance.

THE PROGRAM IS PROVIDED "AS IS". THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.

The binding legal text is the GNU General Public License, version 3, published by the Free Software Foundation at https://www.gnu.org/licenses/gpl-3.0.html.

9. Apache License 2.0 (Apache-2.0)

Permissive like MIT, plus an express patent license from contributors, a requirement to state significant changes, and NOTICE-file preservation. Official text: https://www.apache.org/licenses/LICENSE-2.0

What this allows

Commercial use, modification, and distribution are allowed.
Contributors grant a patent license for their contributions.
Keep the license, state significant changes, and preserve NOTICE.
No trademark rights are granted.

Full license text

Apache License
Version 2.0, January 2004
http://www.apache.org/licenses/

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Operative terms (the official legal code is Apache License 2.0):

1. Grant of Copyright License. Each Contributor grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare Derivative Works of, publicly display, publicly perform, sublicense, and distribute the Work and such Derivative Works in Source or Object form.

2. Grant of Patent License. Each Contributor grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as stated) patent license to make, have made, use, offer to sell, sell, import, and otherwise transfer the Work, where such license applies only to patent claims licensable by such Contributor that are necessarily infringed by their Contribution(s) alone or by combination of their Contribution(s) with the Work. If you institute patent litigation, the patent licenses granted to you under this License terminate as of the date such litigation is filed.

3. Redistribution. You may reproduce and distribute copies of the Work or Derivative Works in any medium, with or without modifications, provided you give any other recipients a copy of this License; cause modified files to carry prominent notices stating that you changed the files; retain all copyright, patent, trademark, and attribution notices from the Source form; and, if the Work includes a NOTICE file, include a readable copy of the attribution notices within Derivative Works as required by the License.

4. Submission of Contributions. Unless you explicitly state otherwise, any Contribution intentionally submitted for inclusion in the Work is under the terms of this License.

5. Trademarks. This License does not grant permission to use the trade names, trademarks, service marks, or product names of the Licensor, except as required for reasonable and customary use in describing the origin of the Work.

6. Disclaimer and Limitation. THE WORK IS PROVIDED "AS IS", WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND. IN NO EVENT SHALL ANY CONTRIBUTOR BE LIABLE FOR ANY DAMAGES OF ANY CHARACTER ARISING AS A RESULT OF THIS LICENSE OR OUT OF THE USE OR INABILITY TO USE THE WORK.

The binding legal text is the Apache License, Version 2.0, at https://www.apache.org/licenses/LICENSE-2.0.

10. BSD 2-Clause (BSD-2-Clause)

A short permissive license. Anyone may use, copy, modify, and distribute the work, including commercially, if they keep the copyright notice and this license text.

What this allows

Commercial use, modification, and distribution are allowed.
Keep the copyright notice and license text.
No warranty or liability is accepted.

Full license text

BSD 2-Clause License

Copyright (c) [year] [copyright holder]

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

11. CC BY 4.0 (CC-BY-4.0)

Anyone may share and adapt the work for any purpose, including commercially, if they give appropriate credit, provide a link to the license, and indicate if changes were made. Official deed: https://creativecommons.org/licenses/by/4.0/

What this allows

Sharing and adaptation are allowed, including commercially.
Credit the author and link to CC BY 4.0.
Indicate if changes were made. No extra legal terms that restrict the license.

Full license text

Creative Commons Attribution 4.0 International

Copyright (c) [year] [copyright holder]

This work is licensed under the Creative Commons Attribution 4.0 International License.

You are free to:

  Share — copy and redistribute the material in any medium or format.
  Adapt — remix, transform, and build upon the material for any purpose, even commercially.

The licensor cannot revoke these freedoms as long as you follow the license terms.

Under the following terms:

  Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.

  No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.

No warranties are given. The license may not give you all permissions necessary for your intended use (for example, publicity, privacy, or moral rights may still apply).

The binding legal code is CC BY 4.0: https://creativecommons.org/licenses/by/4.0/legalcode

12. CC BY-SA 4.0 (CC-BY-SA-4.0)

Same as CC BY, plus share-alike: adaptations must be licensed under CC BY-SA 4.0 (or a compatible license). Official deed: https://creativecommons.org/licenses/by-sa/4.0/

What this allows

Sharing and adaptation are allowed, including commercially.
Credit the author and link to CC BY-SA 4.0.
Adaptations must use the same license (share-alike).

Full license text

Creative Commons Attribution-ShareAlike 4.0 International

Copyright (c) [year] [copyright holder]

This work is licensed under the Creative Commons Attribution-ShareAlike 4.0 International License.

You are free to share and adapt the material for any purpose, even commercially, under these terms:

  Attribution — Give appropriate credit, provide a link to the license, and indicate if changes were made.

  ShareAlike — If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.

  No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.

No warranties are given.

The binding legal code is CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/legalcode

13. CC BY-NC 4.0 (CC-BY-NC-4.0)

Anyone may share and adapt the work with attribution, but only for non-commercial purposes. Commercial use needs a separate permission. Official deed: https://creativecommons.org/licenses/by-nc/4.0/

What this allows

Sharing and adaptation are allowed for non-commercial purposes.
Credit the author and link to CC BY-NC 4.0.
Commercial use requires a separate written permission.

Full license text

Creative Commons Attribution-NonCommercial 4.0 International

Copyright (c) [year] [copyright holder]

This work is licensed under the Creative Commons Attribution-NonCommercial 4.0 International License.

You are free to share and adapt the material under these terms:

  Attribution — Give appropriate credit, provide a link to the license, and indicate if changes were made.

  NonCommercial — You may not use the material for commercial purposes.

  No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.

No warranties are given.

The binding legal code is CC BY-NC 4.0: https://creativecommons.org/licenses/by-nc/4.0/legalcode

14. CC0 1.0 (Public Domain) (CC0-1.0)

You waive copyright and related rights to the fullest extent allowed by law. Anyone may use the work for any purpose, including commercially, with no attribution required. Official statement: https://creativecommons.org/publicdomain/zero/1.0/

What this allows

All copyright and related rights are waived to the extent allowed.
Anyone may use the work for any purpose, including commercially.
Attribution is appreciated but not required.

Full license text

CC0 1.0 Universal

[copyright holder], [year]

The person who associated a work with this deed has dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.

You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission.

In no way are any of the following rights affected by CC0:
  — Patent or trademark rights held by the person who associated them with this work.
  — Rights other persons may have in the work or in how the work is used, such as publicity or privacy rights.

Unless expressly stated otherwise, the person who associated a work with this deed makes no warranties about the work, and disclaims liability for all uses of the work, to the fullest extent permitted by applicable law.

The binding legal code is CC0 1.0: https://creativecommons.org/publicdomain/zero/1.0/legalcode

15. Proprietary (LicenseRef-Proprietary)

You keep ownership and grant only the rights you write below. Use this for paid or negotiated licenses. The draft is a starting point — edit it so it matches what buyers may actually do.

What this allows

The author keeps ownership of the work.
Only the rights written in the project terms are granted.
All other rights remain reserved.

Full license text

PROPRIETARY LICENSE

Copyright (c) [year] [copyright holder]. All rights reserved.

This work is proprietary. Title and all intellectual-property rights remain with the copyright holder.

Subject to payment of any applicable fees and to the project terms attached to this work, the copyright holder grants the licensee a limited, non-exclusive, non-transferable, non-sublicensable license to use the work solely as described in those project terms.

Except as expressly granted in writing:
  (a) no copy, modification, distribution, public performance, or derivative work is permitted;
  (b) no license is granted under any patent, trademark, or other right by implication or estoppel;
  (c) confidential information in the work must not be disclosed.

This license terminates automatically if the licensee breaches it. Upon termination the licensee must stop using the work and destroy copies in its possession, except as required by law.

THE WORK IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY ARISING FROM THE WORK.

16. Custom License (LicenseRef-Custom)

Use this when no standard license fits. Start from the draft, then rewrite the grant, restrictions, and disclaimer so they say exactly what you allow.

What this allows

Only the terms you write below apply.
Say clearly what is allowed, what is forbidden, and who is liable.

Full license text

CUSTOM LICENSE

Copyright (c) [year] [copyright holder].

The project terms attached to this work are the license. If those terms are empty, no license is granted and all rights remain reserved.

Where the project terms are silent, the following default rules apply:
  — no right is granted by implication;
  — copyright and related rights stay with the author;
  — THE WORK IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND.