What the response contains
A domain object lists its status, name servers, contacts where published and an events array. Each event has an eventAction (registration, expiration, last changed, transfer and others) and an eventDate in RFC 3339 format. The expiration action marks when the object is removed from the registry at a predetermined time, which is the domain’s expiry date.
RDAP and WHOIS
WHOIS returns free text whose layout differs between registries. ICANN announced that from 28 January 2025 the Registration Data Access Protocol (RDAP) is the definitive source for generic top-level domain registration data, in place of sunsetted WHOIS services.
An example response
An abridged, made-up answer for a domain: {"objectClassName": "domain", "ldhName": "example.com", "events": [{"eventAction": "registration", "eventDate": "2011-03-02T10:00:00Z"}, {"eventAction": "expiration", "eventDate": "2027-03-02T10:00:00Z"}]}. A monitor reads the item whose eventAction is expiration, converts eventDate to a date and counts the days left. If the registry’s answer has no such item, the honest result is “unknown”, and the alert should say so.
RDAP servers may rate-limit or refuse bursts of requests, so a monitor should keep each answer for hours and ask about a domain once a day: registration dates change slowly, and a day’s delay costs nothing.
What to check
Whether the registry for your domain offers RDAP and publishes an expiration event. Some country-code registries do not. Treat a missing date as unknown, never as a safe answer.
Sources
Read on . Standards and vendor pages change; confirm the current text before you rely on it.
- RFC 9083, JSON Responses for RDAP (www.rfc-editor.org)
- ICANN, Launching RDAP; Sunsetting WHOIS (www.icann.org)