Note: This series is targeted at people trying to gain an advanced understanding of Quill and Parchment. If you're just trying to get started with an easy, well-featured editor, it might be good idea to check out Quill's Quickstart Guide or Cloning Medium with Parchment guide.
What is Quill?
QuillJS is a modern rich text editor built for compatibility and extensibility. It was created by Jason Chen and Byron Milligan and open sourced by Salesforce. Since then it has been used by hundreds of other companies and people to build fast, reliable, and rich editing experiences in a browser.