Etherpad (previously known as EtherPad)[2][3] is an open-source, web-based collaborative real-time editor, allowing authors to simultaneously edit a text document, and see all of the participants' edits in real-time, with the ability to display each author's text in their own color.

First launched in November 2008, the software was acquired by Google[4] in December 2009, and released as open source later that month.

The software auto-saves the document at regular, short intervals, but participants can permanently save specific versions (checkpoints) at any time.

Etherpad itself is implemented in JavaScript, on top of the AppJet platform, with the real-time functionality achieved through Comet streaming.

This led the developers to temporarily revert the tool to closed beta, not allowing new pads to be created (but providing full and unrestricted access to the existing ones), while the server infrastructure was being improved.

[17] Google released the source code for Etherpad under the Apache License version 2.0 on December 17, 2009.

[19] After the release of the software as open source, a number of people have set up Etherpad servers,[20] as clones of the original website.

Their website maintains a list of a growing number of sites that run the Etherpad software.