WebTorrent is a client that streams torrents inside a web browser. It plays videos instantly when given a torrent magnet link. If you need a torrent index you can use 1337x.
For Streaming Torrents — Use The WebTorrent App
If you are interested in streaming torrents using an app — see the WebTorrent Desktop app. This is a very reliable streaming application. It’s open source — the code is on Github. Available for Ubuntu, macOS, and Windows.