Discontinued (June, 2017) instant messaging and VoIP service built on open standards provided by Google that could be accessed through Gmail. Also known as Google Chat.
Using the Extensible Messaging and Presence Protocol (XMPP), Google Talk was an instant messaging and voice over IP application that allows users with a Google account to text and video chat from within their browser.
It used to have a Windows client but it was deprecated on 2015.
The Google Talk app for Windows was shut down on February 23, 2015. If you try to use the Google Talk app, you'll see a sign-in error, and we'll send you an email explaining what's happened.