NameRobo
Domain Availability Checker
How a domain availability check actually works under the hood
When you type a domain name into a checker, the tool queries either WHOIS or the newer RDAP protocol to ask the registry whether that name is registered. Registries hold the authoritative record — they are the source of truth for whether a domain exists. Registrars (the companies you buy from) cache registry data, which means a registrar query can lag behind the registry by minutes. RDAP, standardized by ICANN in 2019, returns structured JSON rather than WHOIS's free-text output, which makes it faster to parse programmatically. Two checkers can return different results for the same domain within seconds of each other because they query different layers of this system.
Why a single check is rarely enough
Three scenarios cause a "available" result to become "taken" before you complete a purchase. First, speculative registration: some registrars begin a domain hold when you add it to a cart, blocking others for 15–60 minutes. Second, drop-catching: domains that expire sit in a redemption window, then a 5-day pending-delete period, before becoming genuinely available — and drop-catching services automate registration attempts the moment the domain clears. Third, registry lock states can make a domain appear registered even when it has expired but not yet been released. Checking multiple times across a few hours before purchasing catches most of these false-available signals.
A practical pre-purchase workflow
Start with a bulk availability check during brainstorming to triage dozens of candidates quickly — most tools let you check 10–50 names at once. Before purchasing, re-check the specific domain you have chosen inside the registrar's own cart flow, since that triggers a live registry query rather than a cached one. Run a trademark search in parallel: an available domain with a conflicting trademark is worse than no domain at all, because you may be forced to rebrand after launch spending. Register the chosen domain before you share it publicly — even informal social media mentions can trigger squatting within hours.
Common questions
Why does one tool say a domain is available and another says taken?
The two tools are likely querying different layers — one hits the registrar cache while the other queries the registry directly. Registry data is always more authoritative. Timing also matters: a domain can be registered between two consecutive checks if someone else is actively purchasing it at the same moment.
How quickly can a domain be registered after someone searches for it?
Registration takes seconds once a buyer completes a purchase. Some registrars also use "domain tasting" or cart-hold practices that temporarily block a domain for other buyers. Practically speaking, a name you see available today can be taken within hours if it is attractive and your search is not private.
Is checking availability the same as reserving the domain?
No. A check only reads registry data — it does not write anything. The domain remains available to anyone until a registration transaction completes and the registry records the new owner. Some registrars offer a brief cart hold, but that does not constitute a reservation in any contractual sense.
What's the difference between WHOIS and RDAP?
WHOIS is a 1982 protocol that returns free-text output — human-readable but inconsistent across registries. RDAP (Registration Data Access Protocol), standardized in 2019, returns structured JSON that is easier for tools to parse and includes standardized privacy redactions. RDAP is the current ICANN standard and is gradually replacing WHOIS.