Does CountLink need a server to keep timers in sync?

No. The countdown's end time is written into the shared link as a timestamp when you press Start. Every device that opens the link reads that same timestamp and counts down to it using its own local clock — there's no server involved after the link is generated, and no ongoing connection to maintain.

What exactly is stored in the link?

Two pieces of information: the exact moment the countdown should reach zero (a Unix timestamp), and the label you typed in — nothing else. No personal data, no session identifier, no account reference.

Why can't the timer be paused or extended for everyone at once?

Because there's no live connection between devices, there's no channel to push a pause command through. Each device is independently doing local math against the timestamp in its own copy of the link — there's no shared, ongoing session to interrupt. The practical fix if plans change is starting a fresh countdown and sharing the new link.

How it works

The link is the sync

No server keeps score. Here's exactly what happens between pressing Start and everyone's screen hitting zero together.

Why "just start a timer" doesn't work

If several people each start their own countdown for the same event, they'll start it a second or two apart — one clicked slightly later, one's app took a moment to load. Multiply that by a class or a webinar audience, and "everyone's timer" quietly becomes many slightly different timers. The usual fix is a server acting as one central clock every device connects to — which works, but costs money per connected device, and is why most shared-timer products cap free viewers.

CountLink's approach

Instead of a server tracking how much time is left, CountLink calculates the one fact that matters — the exact moment the countdown should hit zero — the instant you press Start, and writes it into the URL as a timestamp. Anyone who opens that link, on any device, reads the same timestamp and subtracts it from their own clock. No round trip to a server is needed, because the link already contains the answer.

Every screen is doing the same subtraction against the same number — the moment it read out of the link, minus its own clock. Nothing is pushed to them and nothing is held open for them, which is why there is no viewer limit and nothing that can go down mid-countdown.

Step by step

Set a duration — directly on the board by rolling or typing the digits, or below it with a quick preset or an exact date and time — and, optionally, a label like "Exam ends."
The moment you press Start countdown, your browser calculates the target timestamp entirely on your own device.
That timestamp and label are encoded into a URL, which you send however you'd send any link.
Everyone who opens the link reads the same timestamp and starts a local countdown to it using their own device's clock.
Every screen reaches zero at the same instant, because they were always counting down to the same fixed point in time.

What this means in practice

No account. The countdown lives entirely in the link, so there's no user record to attach it to.

No viewer limit. Serving the same static page to one more viewer costs nothing, since nobody's holding a connection open per viewer.

Sync accuracy tracks device-clock accuracy. Each device does its own math against its own clock, so the countdown is only as precise as that clock — typically within a second on a modern phone or computer.

The trade-off: nothing can be pushed mid-countdown. With no ongoing connection between devices, there's no channel to broadcast a live pause to everyone who already has the link open — the fix is starting a new countdown and sharing it. Anyone who specifically needs live control pushed to an audience should see how CountLink compares to real-time tools.