Is kendo UI for jQuery free to use?

Question

I know there is pricing for using Kendo UI. But in other hands, kendo provides CDN service to use kendo WIDGET. So I am confused that If it is providing service then why it has the price for it.

Answer 1

Take a look at their github page. They are releasing part of their UI using the Apache v2.0 License, which, as it is a permissive open-source license, indicates that you can in fact use some, but not all of their features for a commercial project without having to pay.

The kendo 'Core' code can thus be used for any purpose you see fit and they're not able to exercise copyright to stop you, provided you fulfil the terms of the Apache license.

Alternatively, if you buy a professional license from them, you are also allowed to use the full range of UI features. Of course you can't redistribute, Kendo holds the copyrights to e.g. its grid feature. That being said, any code and content you create and present using the UI will by default have all its rights reserved by you.

And a third alternative is to use their CDN. As you noted, usage of the CDN is essentially free; it comes with the caveat that a user also sends a page view to their site. The big caveat is that Telerik is free to add in far more restrictions than with its other two products, where by their very nature such restrictions are impossible to create. As Telerik provides code, the programmer could remove advertisement or spying by modifying it. Not so much when you use the CDN: the code behind it could be closed. A cursory look at their terms of use indicates that they do add some potentially nasty restrictions, including, but not limited to:

1. Claiming copyright over data presented using their CDN.

This is a pretty large restriction. You're essentially giving away the rights to whatever creative thing you make using their CDN for at least 120 years.

2. Restricting content available. Especially the third rule (quote):

is threatening, tortious, defamatory, libelous, indecent, obscene, pornographic, invasive of another’s privacy, or promotes violence; or

These are subjective terms, so Telerik is free to censor your data to a surprising degree if it is in its interests. A bit further down the terms, there's this line, making the full extent of what Telerik can do pretty clear;

Telerik reserves the right, in its sole and absolute discretion for any reason or no reason, to remove or modify any Content, or any other element of the Sites or the Services, without notice or permission from you.

3. Include hidden anticompetitive clauses. E.g. you can't use Kendo's UI CDN to make a site about your own UI. Although this is somewhat small of an issue: you obviously would want to use your own UI to advertise itself!