Dart is free and open source.
See LICENSE and PATENT_GRANT.
Visit dart.dev to learn more about the language, tools, getting started, and more.
Browse pub.dev for more packages and libraries contributed by the community and the Dart team.
If you want to build Dart yourself, here is a guide to getting the source, preparing your machine to build the SDK, and building.
There are more documents on our wiki.
The easiest way to contribute to Dart is to file issues.
You can also contribute patches, as described in Contributing.