Hold a YouTube live at a fixed delay so you and your friends stay frame-synced — everyone reacts to the goal at the same instant. Built for World Cup 2026 live watch-alongs over Discord.
One-click: Install from the Chrome Web Store (works on Chrome / Brave / Edge / any Chromium). Firefox Add-ons (in review — coming soon).
Now (manual): download the latest release, unzip, and load unpacked:
- Chrome / Brave / Edge:
chrome://extensions→ Developer mode → Load unpacked → the unzipped folder - Firefox:
about:debugging#/runtime/this-firefox→ Load Temporary Add-on →manifest.json(temporary — removed on restart)
Open a live, click the toolbar icon, set the target delay. Everyone in the group sets the same number → synced. Each live remembers its own delay (different lives have different latency floors), so the popup slider sets the target for the live you're watching. An optional debug HUD (off by default) shows the live sync status.
YouTube's player already knows how far behind live you are — the same reference for every viewer — so there's no custom clock/NTP:
- Read YouTube's own Live Latency for the stream — the same number every viewer sees.
- Nudge
video.playbackRate(up to 2× to catch up, down to 0.8× to ease back) to hold your target. - Same target everywhere → same captured frame → synced.
It only acts on a live stream and only while you're at the live edge — scrub back to review a replay and it leaves your playback speed alone. It never changes the speed of ads or normal (non-live) videos (it doesn't fast-forward or skip them — it simply doesn't touch them). Optional HUD (top-left): lat 12.3s → 10s 1.20x.
- Can't sit closer to live than the broadcaster's real latency floor — the player can't show frames that haven't arrived yet.
- 2× catch-up sounds chipmunky (pitch-corrected catch-up is on the roadmap).
No data collection, no servers, no network calls. The only thing stored is your settings (target + toggles), kept locally via chrome.storage.sync. The single permission is storage; content scripts run only on youtube.com/watch* and /live/*.
See CONTRIBUTING.md. It's vanilla JS — no build step, no dependencies.
GPL-3.0-only — GNU General Public License v3.0 only.