Guides WHOIS
What is WHOIS (RDAP)?
Every domain is registered with a registrar, and that registration is recorded in a registry. WHOIS is the classic way to query that registry: 'whose domain is this, and until when?'. RDAP (Registration Data Access Protocol) is the modern successor: the same idea, but with clean, structured data instead of loose text. It's handy for checking a domain's status, seeing when it expires, or verifying it's with the right party.
WHOIS and RDAP: what's the difference?
WHOIS has existed since the early days of the internet and returns the data as plain text. Convenient for people, awkward for computers, and formatted slightly differently per registry. RDAP does the same but delivers clean, structured data (JSON) with a fixed shape. That makes it more reliable to read.
For the generic domains (like .com) that switch has already happened: since early 2025 RDAP is the official standard there and registrars no longer have to offer WHOIS. Country domains (like .nl) set their own pace. Many already offer RDAP. DNS Radar's WHOIS tool uses RDAP under the hood.
What you get from it
A typical lookup gives, among other things:
- the registrar (the party the domain is registered with)
- the creation date and the expiry date
- the status (e.g. whether the domain is locked against transfer)
- the nameservers
- whether DNSSEC is enabled (according to the registry)
The expiry date in particular is worth watching: forget to renew and your website and mail stop, and after a short grace period someone else can register the domain.
Why contact details are often missing
In the past WHOIS simply showed the owner's name, address and email. Since privacy laws (like the GDPR) those personal details are usually redacted or replaced with those of a privacy service. So you'll often see the registrar and the dates, but not who the person behind the domain is. That's normal and not an error.
What you use it for
- Checking when a domain expires (yours or someone else's)
- Seeing which registrar a domain is with, e.g. before a transfer
- Verifying a domain is locked against unwanted transfer
- Checking whether a domain is still free to register
In DNS Radar you'll find this under the WHOIS tool. From a DNS scan you can click straight through.
Frequently asked questions
Is WHOIS the same as DNS?
No. DNS tells you where a domain points (which server). WHOIS/RDAP tells you who registered the domain and when it expires. Two different questions.
Why don't I see a name and address?
Due to privacy laws personal details are usually hidden. You'll see the registrar and the dates, but usually not the person.
What exactly is RDAP?
The modern successor to WHOIS: the same data, but in a clean structured form (JSON) that computers can read reliably. For generic domains like .com, RDAP is now the official standard.
Can I see whether a domain is free?
Yes. If the lookup returns 'not found' (a 404 in RDAP), the domain probably isn't registered yet.