Open Source: What It Is and How to Contribute

The MIT license is a short and simple permissive license with conditions only requiring preservation of copyright and license notices. Licensed works, modifications, and larger works may be distributed under different terms and without source code.

The following table summarizes this license:

Permissions	Conditions	Limitations
✓ Commercial use ✓ Distribution ✓ Modification ✓ Private use	⚠ License and copyright notice	✗ Liability ✗ Warranty

The entire text of the MIT license is quite understandable and brief. Note how short and sweet it is: MIT License¹.

Copyright (c) [year] [fullname]

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.

The Apache License 2.0 is a permissive license whose main conditions require preservation of copyright and license notices. Contributors provide an express grant of patent rights. Licensed works, modifications, and larger works may be distributed under different terms and without source code.

The following table summarizes this license:

Permissions	Conditions	Limitations
✓ Commercial use ✓ Distribution ✓ Modification ✓ Patent use ✓ Private use	⚠ License and copyright notice ⚠ State changes	✗ Liability ✗ Trademark use ✗ Warranty

The entire text of the Apache License 2.0 is much longer than that of the MIT license. If interested in the details, see Apache License 2.0⁵.

The GNU General Public License v3.0 is considered a strong copyleft license whose permissions are conditioned on making available complete source code of licensed works and modifications, which include larger works using a licensed work, under the same license. Copyright and license notices must be preserved. Contributors provide an express grant of patent rights.

The following table summarizes these conditions:

Permissions	Conditions	Limitations
✓ Commercial use ✓ Distribution ✓ Modification ✓ Patent use ✓ Private use	⚠ License and copyright notice ⚠ State changes	✗ Liability ✗ Warranty

The text of the GNU General Public License v3.0 license is even longer than the full text of Apache License 2.0 is available from GNU General Public License v3.0⁹.