Ace is an embeddable code editor written in JavaScript
lightweight library for adding IDE style behaviors to plain text areas
CodeJar is a micro code editor for the browser
CodeMirror is a versatile text editor implemented in JavaScript for the browser
1KB code editor for browser with plugins
a modern WYSIWYG editor built on top of CKEDITOR
Open Source browser based html5 enabled rich text editor
Started back in 2003. Has both iframe and inline style rich-text editing
a Dojo-based rich text editor component
a rich text editor framework for React
Open Source online editor providing collaborative editing in really real-time
A simple to use rich text editor, with mobile support, lots of examples, high performance and inline editing
Simple rich text editor (contentEditable) for jQuery UI
WYSIWYG jQuery Plugin
Open Source HTML editor
universal markup jQuery editor
Warning: Not actually used by Medium
A clone of medium.com inline editor toolbar. Uses contenteditable API to implement a rich text solution.
Abandoned in 2012
Free cross-browser WYSIWYG editor
From the maker of CodeMirror
Quill is a free, open source WYSIWYG editor built for the modern web
Advanced, clean and smooth, Redactor Rich Text Editor offers an excellent immersive user experience
Collaborative web-based rich text editor
From the Guardian team
Rich text editor built on top of React and Immutable
HTML5 rich text editor
Bootstrap dependent rich-text editor
Lightweight (19.5 KB) and very useful HTML editor
From the makers of TinyMCE
Used by much of the wordpress and drupal community
Rich text editor for Vue.js
Basecamp's rich text editor
light, translatable and customisable jQuery plugin
Open Source XHTML editor focusing on semantic markup
Made by Voog
a Yahoo! rich text editor component