It's a bit hard to answer your question as stated, since your needs are rather vaguely defined.
Let me explain: Copyleaks tests for plagiarism on the web by finding copies of the submitted document. It supports only certain file types, and it generates a report in a specific format. As an example, I have a story that I've submitted to three sites called Predator (http://archiveofouro...g/works/3732415). Since that's actually behind a ratings barrier, I got no results.
Testing with The Wolf and The Were (http://archiveofouro...hapters/8671774), I would expect it to return the copies I have on fictionpress.com and wattpad.com. I didn't. Instead, I got a reference to something completely unrelated.
So, after running two tests on my own stories that I know have exact copies floating around, I'm pretty unimpressed by what Copyleaks offers. I'd advise doing testing on your own, though.