Licenses quick reference
Ten licenses that cover most of the open source you will meet, with the identifier to put in your license field. Summaries follow choosealicense.com and were checked in October 2026. This is a reference, not legal advice.
| License | Used by | The user must | Patent grant | Copyleft covers | OSI-approved | Texts |
|---|---|---|---|---|---|---|
AGPL-3.0-or-later | Mastodon | Same as GPL, and offer the source to users over a network | Yes | The whole work, network use included | Yes | SPDX, choosealicense.com |
Apache-2.0 | Kubernetes | Keep the notices, and state their changes | Yes, ends for a patent suit | Nothing | Yes | SPDX, choosealicense.com |
BSD-2-Clause | Homebrew | Keep the copyright and license notice | Not explicit | Nothing | Yes | SPDX, choosealicense.com |
BSD-3-Clause | Go | Same, and not use the authors' names to promote their product | Not explicit | Nothing | Yes | SPDX, choosealicense.com |
CC0-1.0 | GitHub's gitignore templates | Nothing | Explicitly not granted | Nothing | No | SPDX, choosealicense.com |
GPL-3.0-or-later | Ansible | Keep the notices, state changes, share the source of the whole work | Yes | The whole work, when distributed | Yes | SPDX, choosealicense.com |
LGPL-3.0-or-later | go-ethereum's libraries | Keep the notices, state changes, share the source of the library | Yes | The library | Yes | SPDX, choosealicense.com |
MIT | React | Keep the copyright and license notice | Not explicit | Nothing | Yes | SPDX, choosealicense.com |
MPL-2.0 | OpenTofu | Keep the notices, and share the source of the files they changed | Yes | The modified files | Yes | SPDX, choosealicense.com |
Unlicense | yt-dlp | Nothing | Not explicit | Nothing | Yes | SPDX, choosealicense.com |
What the columns mean#
- License is the SPDX identifier: the string package managers and compliance tools read. Copy it as written.
- The user must is what the license asks of anyone who uses, changes or shares your code.
- Patent grant says whether contributors license the patents their contribution needs. Apache-2.0 ends that grant for anyone who sues over patents in the project.
- Copyleft covers is how far “changes must come back” reaches: nothing, the modified files, the library or the whole work.
- OSI-approved links to the Open Source Initiative’s page for the license. CC0-1.0 is not approved by the OSI, and says so itself: it waives rights, it does not license the code.
Every one of them disclaims warranty and liability: the code comes as is.
Which one, and what about mixing them#
- Choosing a License: Four Questions and a Table picks one for your project, and shows where to apply it.
- License Compatibility covers the other direction: which of these licenses can mix in one program.
- Licenses for Things That Aren’t Code covers documentation, fonts, hardware and data.
Know a license that belongs here? Suggest it in the Open {re}Source discussions.