Periscope is a live video streaming app for iOS and Android developed by Kayvon Beykpour and Joe Bernstein and acquired by Twitter before launch in 2015.

Periscope users have the option to tweet out a link to their live stream. They can also choose whether or not to make their video public or viewable to only certain users. Scopes can be LBB (Limited by Broadcaster) which disallows comments.

Although the scoper usually simply uses a handheld device such as a smartphone to broadcast, it is also possible to broadcast through Periscope using a professional vision mixing suite such as Wirecast or Teradek using Periscope Pro.

Periscope allows viewers to send «hearts» to the broadcaster by tapping on the mobile screen as a form of appreciation. The maximum number of users that a user can follow is 8,000.

Both the scoper and viewers of the scope are able to block viewers. When blocked by the scoper, users are added to a blocked list, and booted from the scope. If enough scopers block a user, they are blocked from the scope. If they receive more than 4 blocks from 4 different scopes then the user gets shadowbanned.

On 8 September 2015, Techcrunch reported and later confirmed that Periscope was building an AppleTV app. On 10 September 2015, Periscope added the ability to broadcast live in landscape view.