Overview
Introduction
Before registering a domain, or just to settle whether a name is taken, it helps to check the registry directly rather than trust a registrar's often-marketing-driven search page.
This tool asks the domain's registry over RDAP, straight from your browser, and reports whether it currently has a registration record.
What Is Domain Availability Checker?
A domain lookup tool that reports whether a domain name is currently registered or appears free to register.
It's part of this site's DNS & Domain Tools collection and queries a live RDAP server rather than a cached database or a registrar's upsell-laden search widget.
How Domain Availability Checker Works
The domain is sent to rdap.org, which redirects to the correct registry's RDAP server based on the domain's TLD.
An HTTP 404 response, meaning the registry has no record for the name, is read as available. A successful response with registration data means the domain is already registered. Any other failure is reported as an inconclusive error instead of a guess.
When To Use Domain Availability Checker
Use it while brainstorming domain names, to quickly rule out ones that are already taken before checking pricing at a registrar.
It's also useful for confirming a domain that looks unused (no live site) is actually unregistered rather than just parked or dormant.
Often used alongside Domain Age Checker and Domain Expiry Checker.
Features
Advantages
- Queries the authoritative registry directly rather than a registrar's cached search index.
- Fails honestly: an inconclusive RDAP response is reported as an error rather than a false 'available'.
- Works for the vast majority of gTLDs and most ccTLDs, which run standard RDAP servers.
Limitations
- A minority of legacy ccTLD registries don't run RDAP servers, so those domains can't be checked here.
- Some registries don't cleanly return 404 for unregistered names, which can make an available domain look inconclusive; this tool never reports 'available' unless the 404 signal is unambiguous.
- A domain reported as available can still be reserved, on hold, or subject to a registry's own restrictions on registration.
Examples
Best Practices & Notes
Best Practices
- Always confirm availability with a registrar's own checkout flow before assuming a domain is free; this tool is a fast first pass, not a purchase guarantee.
- If a domain reports as available but you expected it to be registered, double-check the TLD is one with reliable RDAP coverage before trusting the result.
Developer Notes
Availability is inferred purely from the RDAP HTTP status: a 404 from queryRdapDomain() sets available: true, a successful record sets available: false, and any other failure (network error, non-404 non-2xx status, missing domain payload) returns success: false with an error message instead of a guessed availability value.
Domain Availability Checker Use Cases
- Screening a shortlist of candidate domain names before checking registrar pricing
- Confirming a domain with no live website is actually unregistered rather than just dormant
- Quickly checking a name idea without navigating a registrar's ad-heavy search results
Common Mistakes
- Treating an 'available' result as a guarantee; registries and registrars can still reject or reserve a name at checkout.
- Assuming an error result means the domain is available; this tool reports errors separately precisely so they aren't mistaken for availability.
Tips
- Pair this with the Domain Age Checker and Domain Expiry Checker: if a domain isn't available, those tools show you exactly how old it is and when its registration lapses.