noUiSlider is open source, and you can use it for free in any personal or commercial product. No attribution required. Both the uncompressed and compressed version of noUiSlider are available in a
.zip release, which is hosted by Github and available over
Release information about the latest Version
Run the unit tests: range and slider.
You can use noUiSlider for free, under the terms of the WTFPL, which allows everything and has no additional restrictions.