Skype :

Skype is a telecommunications application software product that specializes in providing video chat and voice calls from computers, tablets, and mobile devices via the Internet to other devices or telephones/smartphones. Skype additionally provides instant messaging services. Users may transmit both text and video messages, and may exchange digital documents such as images, text, and video. Skype allows video conference calls.

Skype implements a freemium model. Much of the service is free, but Skype Credit or a subscription is required to call alandline or a mobile phone number. At the end of 2010, there were over 660 million worldwide users, with over 300 million estimated active each month as of August 2015. At one point in February 2012, there were 34 million users concurrently online on Skype.

Skype originally featured a hybrid peer-to-peer and client–server system. Skype has been powered entirely by Microsoft-operated supernodes since May 2012. The 2013 mass surveillance disclosures revealed that Microsoft had granted intelligence agencies unfettered access to supernodes and Skype communication content.

Throughout 2016 and 2017, Microsoft redesigned its Skype clients in a way that transitioned Skype from peer-to-peer service to a centralized Azure service and adjusted the user interfaces of apps to make text-based messaging more prominent than voice calling. Skype for Windows, iOS,, Android, Mac and Linux received significant, visible overhauls.