Copyleft

Mon, 01 Jan 0001 00:00:00 +0000

Copyleft is a licensing requirement that derivative works of a licensed work must be distributed under the same (or a compatible) licence. The term is a play on “copyright”: rather than reserving rights, copyleft uses copyright law to compel downstream sharing.

Licenses fall on a spectrum:

None (permissive)

No share-back requirement. MIT, Apache-2.0, BSD, ISC. Derivative works can be relicensed as anything, including proprietary. The trade-off: a proprietary fork can absorb your work without giving anything back.

Concepts on Your License

Copyleft

None (permissive)