Ace (Ajax Code Editor)

Ace is an embeddable code editor built entirely in JavaScript, designed to bring native-level code editing capabilities directly into any web page or JavaScript application. It solves the problem of needing a full-featured, high-performance code editor component that can be seamlessly integrated into web-based tools, IDEs, or any platform requiring code input and manipulation.

The editor supports syntax highlighting for over 110 languages and offers more than 20 themes, with the ability to import TextMate/Sublime Text language and theme files. Key features include automatic indent and outdent, an optional command line, fully customizable key bindings including Vim and Emacs modes, search and replace with regular expressions, code folding, multiple cursors and selections, and live syntax checking for JavaScript, CoffeeScript, CSS, and XQuery. It can handle very large documents and is rendered using the DOM.

Ace is intended for developers building web-based applications that need a code editing interface, such as online IDEs, documentation tools, or code playgrounds. It is an open-source community project hosted on GitHub and released under the BSD license, making it free to use in both open-source and proprietary projects. The editor is embedded via a script tag and configured programmatically, with no mention of a free plan, trial, or paid editions.