This is an alphabetic list of defunct instant messaging platforms, showing the name, when it was discontinued and the type of client.

• AOL Instant Messenger, 1997–2017
• aMSN, 2002–2012
• BBM, 2005–2019
• ChatON, 2011–2015
• Emesene, 2013 – MSNP (Microsoft Notification Protocol or Mobile Status Notification Protocol)
• Empathy
• Fetion
• FireChat, 2014–2018
• Gizmo5, 2005–2011 – Multi protocol
• Google Allo, 2016–2019
• Google Hangouts, 2013–2022
• Hike Messenger, 2012–2021
• iChat, 2002–2012
• Instantbird, 2007–2013
• Meebo, 2005–2012
• Microsoft Kaizala, 2017–2023
• Microsoft Messenger service, 1999–2014
• Microsoft Office Communicator/Microsoft Lync
• MSN Messenger, 1999–2005
• Mxit, 2005–2016
• MySpaceIM, 2006–2009
• Odigo Messenger, 2002–2004
• ooVoo, 2007–2017
• PowWow, 1994–2001
• Skype Qik, 2014–2016
• Surespot, – 2022
• Talk City, 2002
• Upptalk, 2010–2017
• Windows Live Messenger, 2005–2012
• Windows Messenger, 2001–2008
• Xfire, 2003–2015
• Yahoo! Messenger, 1998–2018