What is the difference between RDAP and WHOIS?

Both return registration data for a domain, such as its expiry date and registrar. WHOIS sends free-form text whose layout changes from registry to registry, while RDAP returns structured JSON over HTTPS with standard fields. ICANN now treats RDAP as the official lookup service for generic TLDs.

Can this tool tell me who owns a domain?

Usually not. Since GDPR, most registries and registrars redact the registrant's name and contact details from public records, so RDAP rarely shows them. The checker shows the registrar instead, which is the company to contact about renewal or ownership.

Does the domain expiry checker work for every extension?

It works for every extension whose registry runs an RDAP service listed with IANA, which includes .com, .net, .org and most newer generic TLDs. Some country-code registries do not publish an expiry date via RDAP, or have no RDAP service at all. When that happens, the tool tells you the date is not available.

How many domains can I check for free?

You can run 3 checks a day, one domain at a time, with no account. Results appear immediately on the page. For daily automatic checks on many domains, Deltio offers a 14-day free trial.

Does Deltio alert me before a domain expires?

Yes. Deltio looks up the expiry date of every monitored site's domain via RDAP and sends an email or Slack alert when 30 days or fewer remain. Plans start at £24 a month, or £20 a month billed annually.

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Free domain expiry checker

Check any domain's expiry date, days left, registrar and status codes, taken straight from the registry's RDAP record. Free, with no sign-up.

What this checker looks up

When you enter a domain, the tool asks the registry that runs its extension for the official record, using RDAP (Registration Data Access Protocol). RDAP is the successor to WHOIS: the same kind of data, returned as structured JSON over HTTPS, with a standard format for dates and statuses. ICANN has made it the reference lookup service for generic TLDs such as .com, .net and .org, and many country-code registries run it too.

To find the right server, the checker reads the IANA bootstrap file, which maps each extension to its registry's RDAP endpoint. It then returns the expiry date, the days left, the registrar, the registration date and the domain's EPP status codes. Nothing is scraped from a third-party WHOIS site, so what you see is what the registry holds at the moment of the check.

How to read the result

The expiry date marks the end of the period the domain is currently registered for, and the days left count from today. Anything under 30 days gets a warning. ICANN rules require registrars to send reminders roughly one month and one week before expiry, but those emails often land in the inbox of someone who left the company years ago.

The registrar is the company the domain was bought through. If you or your client do not recognise the name, sort that out before the renewal date, because only someone with access to that registrar account can renew it.

Status codes need a little translation. RDAP writes them in plain words (client transfer prohibited), while registrars and older WHOIS output use the EPP form (clientTransferProhibited). They mean the same thing.

clientTransferProhibited, clientDeleteProhibited, clientUpdateProhibited: locks set by the registrar. Normal, and protective.
serverTransferProhibited and the other server locks: set by the registry, often as a paid registry lock or during a dispute.
clientHold or serverHold: the domain is not published in DNS, so the website and email stop working. This often follows non-payment or a failed contact verification.
autoRenewPeriod: the registry has renewed the domain automatically, and the registrar still has a window to delete it if nobody pays.
redemptionPeriod: the domain has been deleted and only the registrant can recover it, usually for a much higher fee.
pendingDelete: recovery is no longer possible and the name will be released.

Why the expiry date can mislead you

For many generic TLDs, the registry renews the domain automatically on its expiry date and bills the registrar. RDAP then shows a date one year later, even though the registrant has paid nothing. If the registrar does not collect payment, it can delete the domain during the auto-renew grace period, which can last up to 45 days. A domain showing autoRenewPeriod with a fresh expiry date is therefore not safe yet. Check the registrar account.

After deletion comes the redemption period, typically 30 days, then about 5 days of pendingDelete before the name is released. Many registrars also point an expired domain at a parking page soon after the expiry date, so traffic and email stop long before the domain is actually lost.

When there is no expiry date

Some country-code registries do not publish an expiry date over RDAP, or do not run an RDAP service at all. In that case the tool says so instead of guessing, and you will need the registrar's control panel or the registry's own lookup page.

If the domain is not found, either it is not registered (so it may be available) or its extension has no RDAP server listed with IANA.

What to do when the date is close

Log in to the registrar account, confirm whose name the domain is in, and renew for more than one year if the budget allows. Turn on auto-renew and make sure the card on file is still valid. Change the contact email to an address that will still be read in two years: a shared mailbox rather than one person. If the domain sits in a client's account you cannot access, tell them in writing, with the date and the registrar name.

While you are at it, check the SSL certificate too. It expires on its own schedule, and our guide to SSL certificate expiry monitoring covers that side. When you take on a new client, add both dates to your SEO onboarding checklist.

Why a one-off check is not enough

A single lookup tells you the state of one domain today. It will not notice that a card expired, that someone switched off auto-renew, or that the domain slipped into clientHold last week. If you look after dozens of client sites, checking each one by hand a few times a year is exactly the job that gets skipped. There is more on this in our article on domain expiry monitoring.

Automatic domain checks with Deltio

Deltio checks the domain expiry of every site you monitor via RDAP and shows the exact date, days left and registrar in the dashboard. When 30 days or fewer remain, it alerts you by email or Slack. The same account also tracks SSL certificates, uptime every 10 minutes, sitemaps, robots.txt and SEO tags. Plans start at £24 a month, or £20 a month billed annually, and there is a 14-day free trial.

Frequently asked questions

What is the difference between RDAP and WHOIS?: Both return registration data for a domain, such as its expiry date and registrar. WHOIS sends free-form text whose layout changes from registry to registry, while RDAP returns structured JSON over HTTPS with standard fields. ICANN now treats RDAP as the official lookup service for generic TLDs.
Can this tool tell me who owns a domain?: Usually not. Since GDPR, most registries and registrars redact the registrant's name and contact details from public records, so RDAP rarely shows them. The checker shows the registrar instead, which is the company to contact about renewal or ownership.
Does the domain expiry checker work for every extension?: It works for every extension whose registry runs an RDAP service listed with IANA, which includes .com, .net, .org and most newer generic TLDs. Some country-code registries do not publish an expiry date via RDAP, or have no RDAP service at all. When that happens, the tool tells you the date is not available.
How many domains can I check for free?: You can run 3 checks a day, one domain at a time, with no account. Results appear immediately on the page. For daily automatic checks on many domains, Deltio offers a 14-day free trial.
Does Deltio alert me before a domain expires?: Yes. Deltio looks up the expiry date of every monitored site's domain via RDAP and sends an email or Slack alert when 30 days or fewer remain. Plans start at £24 a month, or £20 a month billed annually.