GNU Lesser General Public License v3 (LGPLv3)
A 'weak copyleft' license designed for libraries. Software using the library does not need to be under LGPL, but changes to the library itself must be shared.
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Risk Assessment by Project Type (Proprietary / Commercial)
1. SaaS / Cloud Application (operated by you)
Safe for internal or SaaS use. The constraints only apply in case of distribution.
2. Distributed Software (Dynamic Linking)
CAUTION: You (or your client if they redistribute) must mention the use of the component, provide its source code, and allow its replacement.
3. Distributed / Embedded Software (Static Linking)
DANGER: Static linking with this type of component imposes complex technical and legal constraints (providing object files, allowing relinking).
4. 100% Internal Tool (Undistributed)
Safe for internal or SaaS use. The constraints only apply in case of distribution.
Philosophy & Ideal Use
- Allow the use of open source components in proprietary projects, while ensuring that the component itself remains free.
Your Main Obligations
- Provide the source code of the LGPL component (and its modifications).
- Allow the end-user to replace or update the LGPL component (simpler with dynamic linking).
✓ Permissions
- Commercial use
- Modification
- Distribution
- Private use
- Patent grant
⚠ Conditions
- Share the source code of library modifications
- Include copyright and license text
- Allow the user to re-link with a modified version of the library
✕ Limitations
- No warranty
- Limitation of liability