I built a Chrome extension because Kick's VOD chat can't keep up with 1.5x

I watch most streams as VODs, and I watch them at 1.5x. On Kick that has one annoying side effect: the chat replay falls behind. Someone scores, the streamer screams, and the "GOOOL" wave in chat shows up 20 seconds later.

So I built VOD Chat Sync for Kick, a small Chrome extension that keeps the chat replay in sync with the video at any speed. It's free and open source (MIT).

Why the chat lags

I measured the native replay before touching anything. It fetches message windows at video pace, but it displays them at wall-clock pace (1x). At 2x, after 30 seconds of watching, the native chat was about 40 seconds behind the video. Pausing or seeking realigns it, and then it starts drifting again.

So it's not a network problem. The replay's clock is simply the wrong clock.

The fix: use the video as the clock

Every VOD has the stream's real start time. That gives a simple mapping:

const absoluteTime = vodStartMs + video.currentTime * 1000;

With that, the extension:

Fetches messages from the same endpoint the site uses, in 5-second windows, about 30 seconds ahead of the video.
Renders each message only when absoluteTime passes its timestamp.
Resets the list on a seek (backward, or a big jump forward).

Because the video drives everything, 1.25x, 1.5x, 2x, pause and seek all just work, with no speed-specific logic.

A few details that took longer than expected:

Throttled timers. Chrome throttles setInterval in background or unfocused tabs, so the tick is also driven by timeupdate, seeked, ratechange, play and pause events.
SPA navigation. Kick is a single-page app, so the extension watches location.pathname and tears everything down when you leave a VOD.
Looking native. I matched the chat's spacing, fonts, badges, emotes and replies, and checked 54 messages side by side against the native chat, down to row height.
Being honest about the original. There's an "Original chat" button. My panel covers the native list instead of hiding it, because hiding it with display: none made Kick's replay realign itself, which would make the comparison look better than reality. When you switch, you see the native chat exactly as it behaves.

Privacy

No data is collected. No server, no analytics. Requests go straight from your browser to Kick, the same ones the site already makes. No build step either: what's in the extension/ folder is what runs.