Is MPL 2.0 compatible with GPL 2.0?
MPL 2.0-licensed code is conditionally compatible with a GPL 2.0 project. Here is what that means for your obligations, conflicts, and distribution.
The license of the code you want to use.
The license you are applying to your project.
The short answer
MPL 2.0 is weak copyleft — you must share the source of the specific modified files, but the rest of your project can stay under GPL 2.0.
Key obligations
Keep the MPL 2.0 code in separate files and provide their source if you distribute.
Potential conflicts
File-level boundaries apply. Strong-copyleft targets may pull in more depending on how the code is linked.
Distribution notes
The larger work can be under GPL 2.0, but the MPL 2.0 files stay under MPL 2.0.
Deep-dive resources
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What this means in practice
Mozilla Public License 2.0 is a weak copyleft license and GNU GPL v2.0 (Only) is a strong copyleft license. Whether you can combine them depends on the details: how the code is linked, whether you modify it, and how you distribute it. Treat the obligations below as a starting point and get legal review before a commercial release.
Compliance checklist for MPL 2.0 → GPL 2.0
- Keep MPL 2.0 code in clearly separated files or modules.
- Map which obligations apply to your distribution model (binary, SaaS, or internal).
- Document the boundary between MPL 2.0 and GPL 2.0 code.
- Obtain legal review before a commercial or public release.
About these licenses
Mozilla Public License 2.0
LibraryWeak, file-level copyleft. You must share changes to MPL-covered files, but the rest of your project can use another license.
- Type
- Weak copyleft
- Patent grant
- Express
- Source sharing
- Modified files only
GNU GPL v2.0 (Only)
ProjectStrong copyleft. Distributing a combined work means releasing all of it under GPL v2.0. The "only" variant is incompatible with the GPL v3 family.
- Type
- Strong copyleft
- Patent grant
- None
- Source sharing
- Entire combined work
MPL 2.0 and GPL 2.0: frequently asked questions
Common questions about combining Mozilla Public License 2.0 and GNU GPL v2.0 (Only).
Is MPL 2.0 compatible with GPL 2.0?
MPL 2.0 is weak copyleft — you must share the source of the specific modified files, but the rest of your project can stay under GPL 2.0.
Can I use MPL 2.0 code in a GPL 2.0 SaaS or cloud application?
MPL 2.0 is weak copyleft — you must share the source of the specific modified files, but the rest of your project can stay under GPL 2.0.
What are my obligations when combining MPL 2.0 and GPL 2.0?
Keep the MPL 2.0 code in separate files and provide their source if you distribute. The larger work can be under GPL 2.0, but the MPL 2.0 files stay under MPL 2.0.