Domain expiration monitor

The domain expiration monitor looks up a domain’s registration record at the registry and tracks how many days remain until it expires. Use it to make sure a lapsing registration rolls into your incident channel weeks before the registrar would happily let the domain go.

Configuration

Field	Type	Default	Notes
Domain	hostname	—	Apex domain (example.com, not www.example.com). If you paste a full URL, the scheme, port and path are stripped automatically.
Alert before expiry	days	30	Minimum 1. The monitor turns Degraded when remaining validity drops to this number of days or below.
Timeout	ms	15000	1000–30000. Maximum time per registry lookup.

How it works

Each check queries WHOIS for the domain’s registration record. If WHOIS fails or doesn’t expose an expiry date (common on newer TLDs such as .dev and .app), the monitor automatically falls back to RDAP, the modern structured replacement for WHOIS. The source field in the result data tells you which protocol answered.

Status mapping

Outcome	Status
Expiry found, more than alert_before_expiry_days days remaining	up
Expiry found but within alert_before_expiry_days days	degraded
Registration already expired	down
Both WHOIS and RDAP lookups fail, or no expiry date found	error

A lookup failure is recorded as error rather than down — registry rate limiting or a slow WHOIS server doesn’t mean your domain is in trouble, and an error result won’t trip a status-change alert rule the way down would.

Result data

Field	What it is
domain	The domain that was looked up.
expiry_date	Registration expiry timestamp (ISO 8601).
days_remaining	Whole days until expiry. Negative once expired.
registrar	Registrar of record, when the registry exposes it.
source	Which protocol supplied the data: whois or rdap.

Interval floors

Registration data changes once per renewal cycle, and registries rate-limit aggressive WHOIS callers. Floors apply on top of the plan-wide minimum interval — see Limits & quotas.

Tips

• Run domain monitors against your apex only. Subdomains share the apex’s registration record.
• Pair with an SSL monitor on https://<your-apex> so you catch the more common expiry (the certificate) and the long-tail expiry (the registration) from the same dashboard.
• If a TLD’s registry hides expiry data behind both protocols, the check reports error consistently — treat that as “this TLD can’t be monitored this way”, not as flakiness.