SSynch by emilvdijk

Watch together, actually in sync.

Starting a film "on three" never works. Someone's stream buffers, someone pauses to get the door, and twenty minutes later everyone is a different distance into the same film.

SSynch keeps every player on the same moment. One person creates a room and picks the video; everyone else joins with a six-character code, and their player follows.

How it works

Click the SSynch icon and hit Create room.
Share the six-character code with whoever is watching.
Open your video and hit "Select video on this page". Everyone else's browser opens the same page and locks onto the same video.
Watch. Play, pause and seek from any side — it applies to everyone.
What it does

▸ Works on any site. SSynch attaches to the video player itself rather than to a hard-coded list of streaming services, so it behaves the same on a big streaming service, a self-hosted file, or a lecture recording.

▸ Corrects drift as it goes. No two browsers play at exactly the same speed. Rather than only syncing when somebody clicks something, SSynch keeps comparing positions and correcting — an imperceptible speed nudge for a small gap, a seek for a large one — so you don't quietly drift apart over a two-hour film.

▸ Accounts for lag. Playback positions are corrected for the round-trip delay to the server, so joining late or jumping to a new scene doesn't leave you a second behind everyone else.

▸ Anyone can control it. Pause to get the door, rewind for the line nobody caught — every participant can, not just whoever started the room.

▸ Stays out of the way. A small widget shows who's connected and whether you're in sync. Drag it anywhere, collapse it to a single button, and it stays visible in fullscreen.

▸ Survives real life. It reconnects on its own after a dropped connection, a page reload, or a long pause, and re-finds the video if the player rebuilds itself mid-session.

▸ Nothing to sign up for. No account, no email, no profile. Generate a code and go.

What you'll need

Everyone needs SSynch installed, and everyone needs their own access to whatever you're watching. SSynch synchronises playback — it does not stream, share, or re-broadcast video. If a site needs a subscription, each person still needs their own.

It works with standard HTML5 video players, which covers most of the web. Some heavily customised players behave differently, and sites that block extensions outright won't work.

Privacy

No accounts, no analytics, no tracking, no third parties. To keep a room in sync, SSynch sends the address of the page the host shares, a description of which video element to control, and the playback position. That's the whole list — no page content, and nothing about any other page you visit. Room data is deleted 24 hours after a room was last used. Full policy linked below.