Check availability
Each domain is queried against the registry's RDAP service directly from your browser, with a DNS fallback where the registry has no RDAP. Nothing is logged here.
How it works
Expand the list
Full domains are checked as given. A bare name like acmemail becomes five candidates across .com, .net, .org, .co and .io, up to fifty in total.
Ask the registry
Each domain goes to rdap.org, which redirects to the registry that runs the TLD. A 404 means no such object — available. A 200 returns the registrar, dates and status.
Fall back to DNS
A few country-code TLDs have no RDAP. There the tool checks for a delegation at the TLD: NXDOMAIN on both SOA and NS is reported as probably available, never as certain.
Act on it
Available names get a register link. Taken names expiring inside 45 days are called out — those are the ones worth a backorder.
Why not just search on the registrar
Because a registrar search page answers one name at a time, sets a cookie, and increasingly shows you a “premium” price on names it has no business marking up. When I am picking a batch of secondary sending domains I have a shortlist of twenty or thirty variants — brand plus mail, outreach, try, get, across a few TLDs — and I want one table that says which are free before I go anywhere near a cart. The secondary domain finder generates that list; this tool checks it.
RDAP, and why it beats WHOIS
RDAP is the structured replacement for WHOIS that every gTLD registry has been required to run since 2019. It answers over HTTPS in JSON, with proper status codes: a 404 means the name has no registration, full stop. A 200 returns the registrar, the registration and expiry dates and the EPP status codes, which is how this tool spots a domain in redemption or pending delete — the state a name sits in for roughly 35 days after its owner stopped renewing, before it drops back to the pool. Verisign, Identity Digital, CentralNic and the other large registries all allow browser requests, so the check runs on your device.
What “probably available” means
A handful of country-code registries — .io is the notable one for cold email — either run no RDAP or block browser requests. For those the tool falls back to DNS and asks the TLD whether the name is delegated at all. NXDOMAIN on both SOA and NS almost always means unregistered, but a registered domain with no nameservers looks the same, so it is reported as probable rather than certain. Confirm at the registrar before you plan around it.
Reading the taken ones
A taken domain with an expiry inside 45 days is more interesting than it looks. Most registrars auto-renew, so most of those will renew — but the ones that do not go through grace and redemption and drop, and a backorder placed now catches them. A domain registered years ago and dropping this month is exactly the aged domain the domain age checker would tell you to buy, at registration price instead of aftermarket.
Frequently asked questions
How accurate is the availability check?
For gTLDs it is the registry's own answer via RDAP: a 404 is definitive. For the few TLDs without RDAP the tool falls back to DNS and says “probably available”, which you should confirm at the registrar.
Why is .io sometimes “probably available” instead of “available”?
The .io registry's RDAP endpoint does not reliably accept browser requests, so those names fall back to the DNS check.
Can it check premium pricing?
No. RDAP reports registration state, not price. A name that is available may still be priced as premium by the registry; the register link will show that.
What does “pending delete” mean?
The owner did not renew. The domain sits in a grace and redemption period of roughly 35 days and then drops back to the pool. A backorder at a registrar catches it the moment it drops.
Is there a limit?
Fifty domains per run, four at a time, with a short pause between them so the registries do not rate-limit you. If one does, that domain is retried through the DNS fallback.
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Start with a call
Bring a domain and the symptom. I will tell you what is actually wrong and whether you need me at all — plenty of people leave that call able to fix it themselves.
Thirty minutes, no pitch
We will run the checks together on your actual domains, and you will leave knowing what is broken, what it takes to fix, and what it should cost. If that is a job you can do in-house, I will say so.