Research a domain’s DNS records, RDAP, WHOIS, subdomains, IP addresses, and email security in one report.
Who.is
Who.is searches domain and website registration records, including WHOIS, RDAP, DNS, and related information.
About Who.is
Who.is is a lookup website for domain names and IP addresses. Users can search registration information for a domain, including registrant, registrar, and registration dates, using the WHOIS and RDAP protocols. The site also shows DNS records, nameserver details, IP address ownership and network data, and whether a website is reachable at the time of the check.
The homepage describes paid services for researchers, investigators, and site owners. These include a historical domain report, website monitoring for uptime, DNS changes, and TLS certificate expiry, and API access that returns parsed WHOIS and RDAP data as JSON. Pricing is not stated in the source, and the homepage does not list the plan terms for each service.
Key features
- WHOIS and RDAP registration data lookup for any domain name
- DNS record lookup for A, AAAA, MX, TXT, NS, and other record types
- Nameserver lookup showing which domains a nameserver hosts
- IPv4 and IPv6 address ownership and network data lookup
- Domain history report of historical WHOIS and RDAP records, delivered as a download
- Pro monitoring for uptime, DNS changes, and TLS certificate expiry on up to 10 domains
Best for: Researchers, investigators, and site owners who need domain registration, DNS, IP, and monitoring information in one place.
Good for
- Combines WHOIS, RDAP, DNS, nameserver, and IP lookups on one site
- Monitoring alerts cover downtime, DNS changes, and certificate expiry
- The API description notes a free tier with no card required to start
Watch out for
- Pricing is not stated in the source and is listed as unknown
- Pro monitoring is limited to up to 10 domains as described on the homepage
- Historical coverage depends on how much WHOIS and RDAP data the site holds for a domain
Who.is at a glance
- Website
- who.is
- Category
- Privacy & Security › Website & URL Scanners
- Type
- Website
- Pricing
- Not confirmed. Check the site
- Platforms
- Web
- Open source
- Not stated
- Language
- English
- Last checked
- Oct 6, 2026 · Online when checked
- Listed
- Oct 5, 2026
Who.is alternatives
Tools and sites you could use instead, ranked by how closely they match.
MarkMonitor WHOIS looks up domain registration records, with notices about contact information withheld for some registrations.
ICANN Lookup searches registration data for domain names and related internet number resources.
ViewDNS.info is a web-based collection of DNS, domain, and IP lookup tools, including reverse IP, WHOIS, DNS records, subdomain discovery, port scanning, and traceroute. It also offers an API for domain and IP data.
Freemium
17 alternatives
DomainRecon looks up DNS records, WHOIS details, SSL certificates, and IP addresses for a domain.
DNSai provides DNS lookups and analysis tools for records, WHOIS, blacklists, email authentication, and domains.
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Who.is FAQ
What is the difference between WHOIS and RDAP?
WHOIS is a widely used internet protocol for querying databases of registered users of domain names, IP addresses, and autonomous systems. RDAP (Registration Data Access Protocol) is described as the modern successor to WHOIS, offering a standardized, secure, and more structured way to access registration data.
What does the Pro website monitoring service check?
According to the homepage, it checks uptime, DNS changes, and TLS certificate expiry for up to 10 domains from one setup. It sends notifications when a site goes down, its DNS changes, or its certificate nears expiry.
Is there an API for this data?
The homepage describes Pro API Access, which returns parsed WHOIS, normalized RDAP, and DNS and TLS certificate history for any domain as JSON over HTTPS. It states that you can start on the free tier with no card required.
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