Today YouTube launched a new iPhone-only app called Uptime. Uptime adopts many of the social features commonly found in social video streaming apps like Periscope – live comments, reactions, etc. – and applies them to YouTube videos.

Inside the app, you browse videos in a feed consisting of content shared by people you follow in Uptime. You can also tap the search box at the bottom to search for videos or pick from a list of videos based on your YouTube subscriptions and viewing history.

When viewing a video in Uptime, what you’re watching will be publicly available to your followers in their Uptime feed, so they can join in and watch alongside you. You also have the option to directly share a video with others, whether by sending them a link using the iOS share sheet or by inviting them inside the app.

As a video is being watched, all current viewers are represented by their profile pictures on a track that covers the borders of the screen. As the video moves closer to its end, you’ll be further along the track, and you can manually drag and drop your avatar to navigate through the video. During playback, you can type comments, use one of six built-in reaction emoji, or move your finger around the screen to create a sparkle effect. Videos can be viewed in both portrait and landscape, but currently there is no way to type comments while in landscape.

Uptime is available in the App Store, but it requires an invitation code to setup your account. The code PIZZA is currently working.