Most Telegram directories let the person submitting a channel type in its member count. That number is never checked again. open.tg works the other way round.
Every public Telegram channel and group has a preview page at t.me/username that states its own size. We read that page directly. The submitter supplies a username and a category — nothing else. There is no field anywhere on this site for entering a member count.
A scheduled job re-checks listings in waves: the biggest and fastest-moving ones daily, the long tail weekly. Each listing carries a timestamp showing when we last looked. If a check is stale, the card says so rather than pretending the number is current.
We keep one data point per community per day instead of overwriting the previous figure. That history is what makes “growing” a sortable fact rather than a claim. A channel that bought 50,000 members overnight looks very different from one that added them over three months, and the chart shows which is which.
Private invite links (t.me/+…) can't be verified, so they can't be listed. Neither can channels that have switched their public preview off — if we can't confirm the size, it doesn't go up. Personal accounts aren't communities and are rejected too.
If a community fails three consecutive checks — deleted, renamed, or made private — it's marked dead and drops out of the directory automatically.