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Check compatibility between different SPDX licenses, used by for checking dependency license compatibility.

Build Status Code Climate Test Coverage Code Climate license

n.b. I am not a lawyer and any results should be confirmed with a copyright lawyer if it's important to you.


Add this line to your application's Gemfile:

gem 'license-compatibility'

And then execute:

$ bundle

Or install it yourself as:

$ gem install license-compatibility


On the command-line:

license-compatibility [-h] [-v] [-l] [-r file] [args]

Arguments are a list of licenses or a list of package:license couples. Examples:

license-compatibility MIT GPL-3.0 Unlicense
license-compatibility my_package:ISC other_pkg:BSD-2-Clause

Mixing the two formats is not allowed. Additional args after a --read option are accepted.


  • -l, --list: Print the list of supported licenses.
  • -r, --read FILE: Read arguments from file.
  • -v, --version: Show the program version.
  • -h, --help: Print help message.

In your code:

License::Compatibility.forward_compatibility('MIT', 'GPL-3.0') #=> true


After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to


Bug reports and pull requests are welcome on GitHub at This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.


The gem is available as open source under the terms of the MIT License.