(disclaimer: I work on the Dart team) Good question! The language does not anticipate backwards breaking changes (modulo any bugs we find in the spec), though

(disclaimer: I work on the Dart team) Good question! The language does not anticipate backwards breaking changes (modulo any bugs we find in the spec), though we expect to add features like mixins. The libraries are going through changes now, especially with the introduction of the new Streams API: http://news.dartlang.org/2012/11/introducing-new-streams-api.html http://news.dartlang.org/2012/11/introducing-new-streams-api... The time is good to check out Dart and let us know what features you need for your next commercial project. However, with the libraries evolving right now, I probably wouldn't use Dart for something I need to ship in Q1 of 2013. We love feedback, and there are a ton of features what work today (package manager, compiler to JavaScript, editor, etc) so we hope to hear from you soon :)