Online converter is using Calibre

[JSWolf]

http://www.online-convert.com/ converts eBooks and the converter they are using is Calibre. Are they allowed to use Calibre for this?

[fidvo]

If I recall correctly, Calibre is licensed under the GPL. That means, among other things, that you can use it for whatever the heck you want. Yes, that includes tying it into an online page or service.

Pretty much the only way to break the license is to modify the program's source code and distribute the modified binary without the new source. But the online converter isn't distributing the software, so it's all good.

(Note that I'm making some assumptions here. I haven't actually visited the page to see what exactly it''s doing, so I'm just going off your description)

[eschwartz]

I've used that website once or twice...

As you say, fidvo, they are fully within their right to run calibre on their server and allow people to upload files for conversion.

This is pretty standard SaaS, using a Freemium payment model. calibre is GPL3, not AGPL3, so even if they were modifying the calibre source code for their own use they would not be required to freely publish their changes... but we have no indication they are changing it anyway, as the official source code comes with a powerful command-line backend which can perform standalone conversions anyway.

They also give accreditation to calibre, which is admirably ethical of them :

Our online ebook converter support a variety of input formats like PDF, ePub, HTML, LIT, LRF, mobi and more. Choose the target format you need for your ebook reader below and start converting. If you are not sure what format your reader supports, you can find more information at mobileread.com.
For most ebook conversions on this website, we make use of the great ebook tool Calibre. Please use it in case you need more fine grained settings.

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Note: If you ask Richard Stallman for his opinion, using cloud-hosted software to do your work for you is a sin. You should run your own copy locally, regardless of whether you actually own a device capable of running the software (thinking of people who only use Android/iOS and/or Chromebooks).

[fidvo]

Originally Posted by eschwartz

Note: If you ask Richard Stallman for his opinion, using cloud-hosted software to do your work for you is a sin.

And then he'll spend the next hour explaining the difference between Open Source and Free Software, and another hour explaining why Linux should actually be called Gnu/Linux.

[kovidgoyal]

As has been said it is perfectly fine. There are actually quite a few websites that use calibre as a backend for their conversion services. My only requirement (and this is not a legal requirement, but a moral one) is that if you use calibre to provide a service, it is nice if you mention that somewhere on your website and link back to the calibre website. This website does that, so I have absolutely no complaints.