LicensesLGPL-3.0-only
Weak CopyleftOSI Approved
GNU LGPL 3.0
A library-focused copyleft license that allows proprietary use under conditions, especially around relinking and replacement rights.
Useful when you want stronger protection than MPL but still allow proprietary consumers in some architectures.
Family
Weak Copyleft
Reciprocity
Library-level
Patent Grant
Included
Closed Source
Allowed
What It Lets You Do
- Modification, redistribution, and commercial use.
- Use by proprietary applications under the license terms.
What It Requires
- Modifications to the LGPL library itself must remain under LGPL.
- Recipients must be able to replace or relink the LGPL-covered component.
- Provide source and notices for the covered library portions.
Advantages
- Protects the library core while preserving some commercial adoption paths.
- Stronger reciprocity than file-level copyleft.
Tradeoffs
- Frequently misunderstood by engineering teams.
- Can slow enterprise approval because of linking questions.
Restrictions And Gotchas
- More complex operationally than MPL or Apache.
- Static linking and packaging patterns need legal review.