Domain Availability Checker

Check whether a domain is registered or likely available from public RDAP registration data. The result is an indication, not a registrar guarantee.

Domain name or prefix

For HTTP or HTTPS URLs, only the hostname is used.

What this tool does

RDAP is a structured registration data service used by domain registries. This checker uses it to ask the responsible registry whether a domain record exists.

A Registered result means the registry returned the domain, while Likely available means that registry returned HTTP 404 for the domain.

Unknown is used when the registry cannot provide a reliable answer, including unsupported TLDs, timeouts and registry errors.

How to use the tool

  1. Enter a full domain such as petuja.dev, or enter a name such as petuja to check a curated set of supported extensions.
  2. You may paste an HTTP(S) URL; only its validated hostname is extracted and the URL path is never requested.
  3. Review the primary result and the compact list of other extensions, including any reason shown for an Unknown result.
  4. Treat Likely available as a registration-data indication and confirm availability and price with a registrar before purchase.

Useful applications

  • Compare a project name across common domain extensions before choosing a domain.
  • Check a specific domain's current registration record without using DNS as an availability heuristic.
  • Investigate why a result is Unknown when a TLD has no supported RDAP path or a registry is temporarily unavailable.

Notes and limitations

  • The tool uses the official IANA RDAP DNS bootstrap plus a small set of fixed official overrides for .de, .ch and .li; it does not accept RDAP servers from user input.
  • Missing DNS records do not show that a domain is available, so DNS is not used for the availability decision.
  • Likely available does not account for reserved names, registry restrictions, premium pricing, blocks or other registrar rules.
  • Prefix searches and alternative-extension checks currently query at most 12 curated TLDs to keep the number of external registry requests bounded.
  • The bootstrap is cached briefly on the server and a still-usable older cache can be used when a temporary bootstrap update fails.

Frequently asked questions

Does Likely available mean that I can definitely register the domain?

No. It means the responsible RDAP registry returned HTTP 404, but the name may still be reserved, restricted, premium-priced, blocked or unavailable through a registrar.

Why can the result be Unknown?

Unknown is shown when the TLD is unsupported or the RDAP service times out, is rate limited, returns an unexpected status or reports an error.

Why does the tool use RDAP instead of DNS?

RDAP exposes registration records from the responsible registry, while missing DNS records only describe current DNS publication and cannot establish whether a name may be registered.

Are all TLDs supported?

No. Prefix searches use a curated list of relevant extensions that currently resolve through the cached IANA bootstrap or official overrides, and an unsupported explicit TLD returns Unknown.

More tools in DNS

View all tools in DNS