Instabook

Instabook is a browser extension that makes it easy to convert any web page with content into a stylish and clean Ebook for free.
You can save web pages as EPUB files and read them offline on your computer or Ebook reader.

You also get to preview the cover page of your Ebook before the epub file is generated.

The latest version also allows you to build a multi-chapter Ebook with each chapter being a snapshot of a different page. Read the README file on GitHub for details.

This add-on does the conversion directly in the browser so the text content is not sent to any external servers. Only the images are sent to a remote server endpoint to mitigate CORS issues when downloading the ebook.