GNU LGPL 3.0 (LGPL-3.0)
Like LGPL-2.1 with GPLv3-era patent and anti-tivoization terms. Same linking rules.
Key facts
- SPDX id
- LGPL-3.0-only
- Category
- Weak copyleft
- Copyleft scope
- linking
- Express patent grant
- Yes
- SaaS triggers disclosure
- No
- GPL-compatible
- Yes — compatible with the GPL.
Obligations
When redistributing as open source.
- LGPL-3.0: retain the copyright notice and license text.
- LGPL-3.0: state significant changes made to the code.
- LGPL-3.0: publish the source of any modifications to the library itself.
- LGPL-3.0: modifications to the library must remain under LGPL-3.0.
Internal use only (never distributed)
- LGPL-3.0: retain the copyright notice and license text.
- LGPL-3.0: state significant changes made to the code.
Public SaaS / hosted web service
- LGPL-3.0: retain the copyright notice and license text.
- LGPL-3.0: state significant changes made to the code.
Static linking
- LGPL-3.0: retain the copyright notice and license text.
- LGPL-3.0: state significant changes made to the code.
- LGPL-3.0: publish the source of any modifications to the library itself.
- LGPL-3.0: modifications to the library must remain under LGPL-3.0.
- LGPL-3.0: provide object files or another mechanism so users can relink against a modified version of the library.
Commercial use
Yes. Copyleft is scoped to the library — your own application code can stay proprietary. Publish modifications to the library itself. Static linking requires a relink path for users.
- LGPL-3.0: retain the copyright notice and license text.
- LGPL-3.0: state significant changes made to the code.
- LGPL-3.0: publish the source of any modifications to the library itself.
- LGPL-3.0: modifications to the library must remain under LGPL-3.0.
Permissive: include notices (Apache also needs NOTICE + change statements). Weak copyleft: disclose only the modified library/files and, for LGPL static linking, provide a relink path. Strong copyleft (GPL): NOT possible to keep proprietary if GPL code is in the derivative work. AGPL: same as GPL plus network rules.
FAQ
- Can I use LGPL-3.0 in a commercial product?
- Yes. Copyleft is scoped to the library — your own application code can stay proprietary. Publish modifications to the library itself. Static linking requires a relink path for users.
- Do I have to open-source my code if I use LGPL-3.0?
- Only modifications to the library itself. Code that links against the library is not affected, subject to the linking terms.
- Does running LGPL-3.0 software as a SaaS require source disclosure?
- No. Hosting is not distribution under LGPL-3.0; running it as a service does not trigger source disclosure.
- Is LGPL-3.0 compatible with the GPL?
- Yes — compatible with the GPL.
Compatibility with other licenses
- Is LGPL-3.0 compatible with MIT? Yes
- Is BSD-2-Clause compatible with LGPL-3.0? Yes
- Is BSD-3-Clause compatible with LGPL-3.0? Yes
- Is ISC compatible with LGPL-3.0? Yes
- Is Apache-2.0 compatible with LGPL-3.0? Yes
- Is BSL-1.0 compatible with LGPL-3.0? Yes
- Is LGPL-3.0 compatible with Unlicense? Yes
- Is CC0-1.0 compatible with LGPL-3.0? Yes
- Is LGPL-3.0 compatible with MPL-2.0? It depends
- Is EPL-2.0 compatible with LGPL-3.0? It depends
- Is LGPL-2.1 compatible with LGPL-3.0? It depends
- Is GPL-2.0-only compatible with LGPL-3.0? No
- Is GPL-2.0-or-later compatible with LGPL-3.0? It depends
- Is GPL-3.0-only compatible with LGPL-3.0? Yes
- Is AGPL-3.0 compatible with LGPL-3.0? It depends