How to monitor domain expiry (and why .de and .ch stay silent)
A domain-expiry monitor reads the registration over RDAP once a day and reminds you before it lapses. Registries for .de, .ch and .li do not publish an expiry date at all.
A domain expires the way a certificate does: on a date you could have read, in a system nobody opens until the website has already gone. DNS still resolves for a while, the host is healthy, and the failure looks like an outage of the site. The fix is to watch the registration, not the homepage.
What the monitor actually asks
A domain monitor is a paid monitor type, from Solo upward. The free plan’s types are HTTP, port and ping. The check runs once a day. That interval is fixed, because registration data does not move faster than that and the lookup hits a public registry service (RDAP) that should not be polled every minute. The monitor is pinned to a single probe region for the same reason: the registry’s answer does not depend on whether you ask from Zurich or New York, and fanning the query out would only multiply load on that service.
When the registry publishes an expiry date, reminders use the same ladder as certificates: 30, 14, 7, 3 and 1 day, once each, and only the steps that sit inside the window you set. The default window is 30 days, so all five fire. Shorten the window and the earlier steps drop out.
.de, .ch and .li do not publish an expiry date
This is registry policy, not a gap in the monitor. SWITCH (.ch and .li) and DENIC (.de) answer RDAP and omit the expiration event. Their port-43 WHOIS omits it too. No endpoint, protocol or retry will produce a date those registries have decided not to publish. A domain monitor on one of these names still checks that the registration exists. It will never send an expiry reminder, and the product says so up front rather than leaving years of silence to interpret.
Expiry is not the same outage as “the site is down”
A domain-expiry reminder is a warning, not a down incident. The site can be up on the day you are told the registration ends in a fortnight. Treat it like a certificate reminder: email is the right channel for a date that far away, and someone has to own the registrar login. A status page does not need to announce a renewal you completed quietly. It does need to hear about it if you miss the date and the name actually stops resolving — that part is an HTTP monitor’s job, not the domain monitor’s.