Checking whether a domain is available sounds simple: type it in, see if a site loads. That method is wrong often enough to waste your time. Here is how availability actually works and how to check it properly.
Availability means registration, not a website
A domain is “available” when no one has registered it. That is a separate question from whether a website appears when you visit it. Plenty of registered domains sit with no site at all, and plenty of parked domains show a placeholder page while being firmly owned.
So the only reliable check is the registry record, not your browser.
RDAP is the source of truth
Registries publish ownership data through RDAP, the Registration Data Access Protocol. It replaced the old public WHOIS service for generic domains in early 2025. When you ask RDAP about a domain, the registry tells you whether it has a record for it. No record means available. A record means registered.
This tool checks availability through RDAP, so a result reflects the registry, not a guess from whether a page loads. That is why it can tell the difference between a parked domain (registered) and a genuinely free one.
The traps that catch people out
A few things make a domain look more available, or more affordable, than it is:
- Premium domains. Some unregistered names are flagged by the registry as premium and priced far above the normal rate. They show as available because no one owns them, but the price at the registrar can be hundreds or thousands.
- Parked domains. A domain showing ads or a “for sale” page is registered. It is not available; it is owned by someone hoping to resell it.
- Recently expired domains. A domain can stop resolving while still being in a redemption period, which means it is not yet available to register.
The fix for all of these is the same: trust the registry record, and confirm the price at the registrar before you celebrate.
Check many extensions at once
When you have a name in mind, do not check one extension at a time. Check .com, .io, .co, .ai and a few others together, so you can see the full picture and pick the best free option. The domain name generator on this site does exactly that for each idea it produces, and links you straight to register the ones that are open.
A simple workflow
- Generate or type the names you are considering.
- Let the tool check them across extensions via RDAP.
- Note which are free, and ignore parked or premium traps.
- Confirm the price at a registrar.
- Register before someone else takes it.
Good names go fast. Checking properly, and quickly, is how you get one before it is gone.