Open Source License Compatibility Checker
Free open source license compatibility checker for MIT, Apache, GPL, LGPL, and MPL, with a verdict and the attribution you still owe.
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What is Open Source License Compatibility Checker?
The Open Source License Compatibility Checker compares your project license against every dependency license — MIT, BSD-2/3, Apache-2.0, GPL-2.0/3.0, LGPL-2.1/3.0, MPL-2.0 and AGPL-3.0 — using a bundled rule-of-thumb table. Each dependency gets a colour-coded verdict with a plain explanation, alongside a full ten-by-ten compatibility matrix and distribution reminders, all computed offline.
Key Benefits
- Instant per-dependency verdicts with colour-coded severity
- Plain-language explanations of what each copyleft license demands
- Full matrix view for planning a re-licensing change
- Attribution reminders that keep NOTICE files honest
- Bundled rule table — consistent, offline and free
Common Use Cases
- •Checking a new dependency before adding it to a product
- •Planning a license change across a codebase
- •Auditing an existing dependency tree for conflicts
- •Teaching open-source licensing basics to a team
- •Preparing NOTICE and attribution files for a release
How to Check License Compatibility
- Pick your project license: Choose the license your own code is under — MIT and Apache-2.0 are the common permissive starting points.
- List dependency licenses: Tick every license your dependencies use. The verdict table updates instantly for the whole set.
- Read each verdict: Yellow means notices are enough, orange means copyleft conditions apply, and red means the licenses conflict so one side has to change.
- Mind the distribution duties: Use the attribution reminders to keep copyright notices, license texts and change statements in your releases.
Key Features
- Verdicts for MIT, BSD, Apache-2.0, GPL, LGPL, MPL and AGPL
- Four-level verdicts with plain-English explanations
- Full ten-by-ten compatibility matrix reference
- Attribution and notice reminders for distributions
- Fully offline from a bundled rule table — no API calls
Frequently Asked Questions
Is Apache-2.0 compatible with GPL-2.0?
No. Apache-2.0 is considered incompatible with GPL-2.0-only, mainly because of its patent-termination and indemnification clauses. Apache-2.0 code can be combined with GPL-3.0 code, because GPL-3.0 explicitly accepts it.
Can my MIT project use a GPL dependency?
Only by accepting that the combined work is distributed under GPL. Your MIT code stays MIT, but the whole application must follow the GPL terms when you distribute it. For a permissive product, look for a permissive or weakly-copyleft replacement.
What makes LGPL different from GPL?
LGPL adds a linking exception: other software may call the library while keeping its own license, provided the library is dynamically linked and users can relink or replace it. Static linking folds the full LGPL terms into the combined work.
Is this checker legal advice?
No. It applies a bundled rule-of-thumb table so you can reason about common cases quickly. Real projects — especially commercial ones — should confirm licensing decisions with a lawyer or an OSPO before shipping.