ACE is an open source embeddable code editor. The developers have just launched version 1.0 of ACE along with their new website. ACE is written in Javascript, its features and performance is claimed to match that of native editors such as Sublime, Vim and TextMate. It can be easily embedded in a webpage or Javascript application. It supports syntax highlighting for more than 40 languages and can handle documents with up to 4 million lines of code.

New features in ACE 1.0 include support for Vi and Emacs keybindings, which gives the ability to import TextMate themes, multiple cursors and code folding. Users can also search and replace with regular expressions, and vertical tab-line indicators and code markers are supported.

With the release of version 1.0, there has been a change in its licensing, from the old Mozilla Tri-license (MPL, LGPL and GPL) to a three-clause BSD license. According to the developers, this change in the licensing should make it easier for the users to contribute back to the community project.

After the initial release of ACE at JSConf.eu 2012 in Berlin, the Mozilla Labs Skywriter team decided to merge with ACE. Successor to Mozilla’s Skywriter project (formerly known as Bespin), ACE aimed at creating simplified version of Skywriter’s plugin system as well as some of its extensibility features. ACE uses the Document Object Model (DOM) for rendering; making the editor compatible with a wider range of browsers, while Skywriter was based on the <canvas> HTML element.

ACE is developed by Cloud9 as the primary editor for its online IDE. Source code for ACE 1.0 is available on this page.