Watch a domain's registration expiry (Domain expiry monitor)

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The Domain expiry monitor (API type domainExp, shown in the app as Domain expiration) looks up a domain’s registration and reminds you before it lapses. A missed renewal takes your site, email and every subdomain offline at once, however healthy your servers are - this monitor catches it weeks ahead.

At a glance


API type token	`domainExp`
Runs from	HostTracker’s own internal check network - no location picker
Schedule	every 6 hours, fixed
Lookup	RDAP first, WHOIS as a fallback; one lookup is shared by every monitor watching the same domain
Plan gates	the Domain expiry type is a package feature (`domainExp`)

How it decides

Reminders: when the domain has exactly 30, 7 or 1 day left, the monitor sends an informational reminder to its contacts subscribed to Up (not voice-call contacts), at most once a day per threshold.
Renewal notice: when the registry reports a new expiration date, the same contacts get a notice with the old and new dates.
Down: when the expiration date has passed, or the registry says the domain is not registered.
A registry that times out or errors is simply asked again at the next check; it never produces a Down on its own.

Settings reference

A Domain expiry monitor has no type-specific settings. The name, tags, Full Log, Open Stats and subscriptions work as described in Common monitor fields.

Setting (app label)	API field	Type / allowed values	Default	Plan limits	What it does for you
Domain	`url`	a registered domain name	required	-	The domain to watch. A URL is reduced to its host and a leading `www.` is removed. IP addresses and single-label names are refused.
Interval	`interval`	ignored	6 hours	-	Fixed; a sent value is replaced and the response carries a warning. Cron is not supported either.
Locations	`locations`	not accepted	-	-	Sending pools is refused.

The reminder days are fixed at 30, 7 and 1.

Set it up in the app

On the Sites dashboard, click Add Monitor and choose Domain expiration in Monitoring Type.
Enter the registered domain (for example example.com) in Domain and a name.
Check Alert Subscriptions: reminders go to contacts subscribed to Up, expiry to those subscribed to Down.
Click Save.

Do it with the API or MCP

curl -X POST https://api2.host-tracker.com/monitor \
  -H "Authorization: Bearer $HT_TOKEN" -H "Content-Type: application/json" \
  -d '{ "type": "domainExp", "url": "example.com", "name": "example.com registration" }'

Update the domain or name with PATCH /monitor/{id}, for example {"name": "Main domain"}.

MCP: create_monitor(type="domainExp", url="example.com") - no interval, no pools.

Read the current expiry with GET /monitor/{monitorId}/attached - the domainExp block carries expiresAt (Unix seconds), daysLeft, domain, sharedDomain and checkedAt - or get_monitor(id, expand="attached"). Webhooks receive domain.expiring on each reminder.

What happens next

The monitor shows the expiration date and days left after its first lookup, then refreshes every 6 hours. After you renew, the new date appears at the next lookup and a renewal notice is sent.

Limits and gotchas

Enter the registered domain, not a subdomain: the lookup uses the host as written, and registries generally know only registered domains. This also applies to the attached check, which takes the parent monitor’s host.
Some top-level domains publish no expiration date; the monitor then stays Up without reminders.
403 package_limit - your package does not include Domain expiry monitors.
422 validation_failed with reason: pool_not_supported_for_type - omit locations.