Software License Compatibility Checker
Check whether code under one licence can be used in a project under another, for commercial, SaaS, proprietary, modification and distribution scenarios. Free, no registration.
This tool provides general software licensing information and is not legal advice. License obligations may depend on how software components are combined, modified, distributed and used.
How the checker works
Results come from a deterministic rule engine, not from AI. Each supported licence is described by structured facts taken from SPDX, the Open Source Initiative, the GNU Project and the licence stewards: copyleft strength, source-disclosure scope, attribution, patent and network-use terms. Rules combine those facts with your scenario, and every rule that fires is listed with its identifier.
Compatibility is directional. Using MIT code in a GPL-3.0 project is generally fine, but using GPL-3.0 code in an MIT project means the distributed result must be licensed under GPL-3.0. License A is always the code you want to use; License B is the project it goes into.
Commercial use is not the same as proprietary use. Almost every open-source licence allows commercial use; the question that usually matters is whether you can keep your own source code closed when you distribute or host the result.
The engine is open source: @esdecode/license-checker on GitHub, including every rule and its tests.
What the results mean
- Generally Compatible
- The licence terms generally allow this use; notice obligations may still apply.
- Compatible With Conditions
- The use is generally possible if specific conditions are met, such as providing source code or allowing relinking.
- Potential Conflict
- A conflict is plausible depending on how the code is combined, distributed or licensed.
- Likely Incompatible
- The licence terms, as generally understood, do not permit this combination.
- Manual Review Required
- The terms are proprietary, custom or product-specific and must be read individually.
- Unknown
- A licence could not be identified, so no conclusion is drawn.