TimelineJS is released under the Mozilla Public License (MPL), version 2.0. That means that TimelineJS is free to "use, reproduce, make available, modify, display, perform, distribute" or otherwise employ. You don't need our permission to publish stories with TimelineJS and you don't need to pay us any fees or arrange any further license beyond the MPL. You may also make changes to our source code, although if you use changed code publicly, you must make the source code to your modified version available.
Note that this page is not offered as legal counsel and you may wish to consult your own lawyers.
If you have more questions, feel free to reach out to us.