Blue Oak Council

Permissive licenses are the bread and butter of software development: simple, effective, and on just about everyone’s “go” list. But most information about free and open source software focuses on other, more complex licenses. The Council publishes this list to identify permissive licenses, so that everyone can recognize, rely on, and use them without expensive legal help.

License List

Version 9

This list is also available as JSON and an npm package.

Only the licenses rated Gold, Silver, Bronze, and Lead on this list are Blue Oak certified. You can read more about how licenses are rated below.

Skip To: Model Gold Silver Bronze Lead

Model

The model license demonstrates all the characteristics the council looks for in a permissive open software license.

Gold

These licenses address patents explicitly, use robust language, and require only simple notice of license terms and copyright notices.

Silver

These licenses use robust language but either fail to address patents explicitly or require more than simple notice of license terms and copyright notices.

Bronze

These licenses lack important but nonessential elements of permissive open software licenses or impose additional requirements or restrictions, such as BSD-style prohibitions against endorsement and promotion.

Lead

These licenses lack one or more essential elements of permissive open software licenses or impose unusually burdensome requirements. Many use unclear, jocular, or incomplete language.

About Our Ratings

Members of Blue Oak Council rate licenses on this list according to their collective judgments of permissiveness and legal rigor, based on their legal knowledge and experience advising clients. They focus on the interest of users and distributors, rather than open software creators or broader policy concerns.

The goal is to create a list that can be incorporated by reference into policies for use use open software by organizations large and small. Most organizations will be comfortable accepting software under any license rated Bronze or better. More conservative organizations can require higher-rated licenses.