Toolkit for building rich-text editors on the web. Developed by [[The Guardian]] and others.

An ideal content editor produces structured, semantically meaningful documents, but does so in a way that is easy for users to understand. ProseMirror tries to bridge the gap between Markdown text editing and classical WYSIWYG editors.

https://prosemirror.net/

Very interesting phrase right on the home page about the [[Open Source]] nature ([[MIT License]]) of the code:

If you are using ProseMirror to make profit, there is a social expectation that you help fund its maintenance. Start here

ProseMirror is maintained by [[Marijn Haverbeke]], whose page the Start here links to.

The Guardian article on moving from their previous editor Scribe to ProseMirror is also a good read.