Watch parties on live streams

A watch party works on a live stream that is broadcasting now. The one thing that behaves differently is what "in sync" means, and that difference is deliberate.

Starting one

Nothing about the setup changes. Open the stream, open Watch Along, choose Who can join, and press Start a watch party. Share the link or the QR code the same way. The receipt timeline tells you the stream is live: a mint dot with the word Live, pinned at the right end of the strip once the stream's rewindable length is known, or centered on the strip while it is still working that out.

The one refusal is a premiere that has not started yet. The Start control is disabled with the line This stream has not started yet. You can start a watch party once it goes live, because there is nothing playing to synchronize against. Come back once it is on the air.

Everyone keeps their own live edge

On an ordinary video, a party works by everyone landing on the same second of the same file. A live stream has no such shared second: your copy of the stream and mine have their own front edges, a handful of seconds apart, depending on the network between each of us and the broadcast.

So the party does something else. While the host is playing at the front of their own stream, everyone else is put at the front of their stream rather than at the host's timestamp. In practice that is what people mean by watching live together: nobody is deliberately held back to match a slower connection, and nobody is dragged forward past the end of what their player actually has.

The party only intervenes when you have drifted a noticeable distance behind your own front edge, and then it settles you just inside it rather than jamming you against the very end, which is where a stream tends to stall while it buffers.

Rewinding is yours alone

Scrub back into the stream's history and you leave the live edge. That is allowed, and nothing about it reaches anyone else: the party never rewinds other viewers to follow you, and it never rewinds you to follow somebody else who went back.

What happens next depends on the host. While the host is still watching at the front, the party treats your drift as something to close and brings you back toward the front of your own stream once the gap is wide enough. If the host has themselves gone back into the stream's history, the party behaves like an ordinary video again and matches their position, because at that point there is a shared position to match.

The In sync chip on the party card is the thing to watch. It reads Catching up while the party is closing a gap, and Waiting for the group while your player is stuck on an advert or a buffer and correction is paused.

What live parties do not change

• Chat, reactions, and voice work the same as any party.
• Masks work the same. You appear Masked by default whether the video is live or recorded.
• The receipt timeline stays useful. Receipts are still pinned to the second they were written at, and the strip shows watchers to the left of the live edge as being behind it.

What's next

• Invite a friend to a watch party covers the sharing side.
• Watch Along is the tour of the panel a live party runs in.

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