[JSWolf]

Originally Posted by hobnail

Here's the standard/official validator for Calibre that you can use:

https://www.mobileread.com/forums/sh...ight=validator

You should always check your epubs with that before you submit them to amazon, et. al.

I use both the Calibre editor's validater and epubcheck and make sure both say there are no errors. I do sometimes let warnings go with the Calibre validater but that's my choice.