GreenSock uses a very permissive license that allows you to use the tools for free for everything except a very specific type of commercial use (if you collect a fee from multiple customers for the same app/product/site that uses GreenSock tools) which makes it extremely accessible and business-friendly while providing a small funding mechanism to sustain ongoing support, enhancement, and innovation. The web is littered with abandoned “open source” projects, but GreenSock has a years-long track record of commitment to the platform. This unique licensing model is a key component of that sustainability. If multiple customers are charged a usage/access/license fee of any kind, please simply sign up for a “Business Green” Club GreenSock membership which comes with a special commercial license granting you permission to do so. Click here for details. Joining the club also gets you members-only bonus plugins, classes, update notifications, and more. Please see the licensing page for details.