Open Source License Picker

What this tool does

The common mistake when choosing an open-source licence is treating commercial use and source-disclosure obligations as one question. This picker separates them: commercial use, whether proprietary distribution is allowed, attribution, patent grant, and whether modifications must ship under the same licence. It then returns matching licences with the reasoning attached.

Every dropdown starts empty. Submitting before all questions are answered produces a prompt naming the missing one, rather than silently defaulting to yes and handing back a confident-looking recommendation. The result covers MIT, Apache-2.0, GPL-3.0, BSD-3-Clause, MPL-2.0 and Unlicense, with the obligations spelled out for each.

A compatibility matrix shows whether code under two licences can be combined in one project, and each recommendation explains which answers drove it, which is useful when the choice needs to be justified to a team.

The five questions are kept separate because collapsing them into one yes-or-no choice is how people end up with the wrong licence. Commercial permission and the right to distribute closed source are different questions; a licence can allow the first while requiring source disclosure on distribution. Attribution, an express patent grant, and share-alike on modifications each narrow the field further, and the recommendation names which of your answers actually removed which candidates. Every dropdown begins empty, and an incomplete form produces a message naming the missing question rather than a plausible default. The obligation list matters more than the licence name: it spells out what notices must be retained, whether modified files must be marked, and when source has to be published. Reading only the short name is what leads to surprises later. The compatibility matrix addresses a different problem, namely whether code under two licences can sit in the same distributed work; it is consulted when a dependency arrives with its own terms, which are checked separately from the licence you choose for your own code. Versions matter, because terms change between releases of the same licence. Trademark rights are generally not granted by an open-source licence, and patent language follows the exact text. The result is a general reading of commonly used licences, not legal advice for a specific release.

Key features

• Five explicit questions: Commercial use, proprietary distribution, attribution, patent grant and share-alike are chosen separately, with nothing pre-selected.
• Common licence comparison: MIT, Apache-2.0, GPL-3.0, BSD, MPL and Unlicense are laid out side by side.
• Obligation list: Each result states what must be retained, disclosed or declared, not just the licence name.
• Compatibility matrix: Check whether code under two different licences can be combined in one project.
• Reasons given: The recommendation names the answers that decided it, which helps a team discussion.
• Incomplete-form check: A missing answer is reported specifically instead of producing a default recommendation.

How to use it

1. Answer commercial and proprietary: Start with whether the project is commercial and whether you intend to distribute it closed-source.
2. Fill the rest: Choose attribution, patent grant and whether modifications must use the same licence.
3. Press Recommend: The result area returns matching licences and the reasoning.
4. Read the obligations: Check attribution notices, source disclosure and change declarations line by line.
5. Check compatibility: Use the matrix when third-party code is involved to confirm combination is possible.

Things to keep in mind

• Not legal advice: Results reflect a general reading of common terms; have counsel confirm before a formal release.
• Answer honestly: Choosing no for proprietary distribution excludes permissive licences and changes the conclusion.
• Dependencies differ: Third-party libraries carry their own licences and must be checked separately from the one you pick.
• Versions matter: Terms vary between versions of the same licence; results describe commonly used current versions.
• Trademarks and patents: Licences generally do not grant trademark rights, and patent clauses follow the exact licence text.