Portholes is a replacement for Instapaper or Pocket. The main differences are article sorting and a better parser.
Mozilla's Readability library is the main parser. You can see the call in /app/services/article_fetch.rb. Should Mozilla's Readability library fail, I've written a basic parser as a fall back.
Portholes uses Calibre's ebook-convert to create .mobi and .epub files as seen in /app/services/ebook_creator.rb.
Folder view:
Single article view:
Settings:
Use of Portholes is governed by the GNU AGPLv3 license that can be found in the LICENSE file.