Cold Email Domain Checker: is this domain safe to send from?
Type the domain you plan to send cold email from. You get the six DNS checks I run before a single message goes out, with the exact fix for anything that fails.
- You enter
- A domain and one yes or no
- You get
- OK, check or fix on six checks, with the fix
- Takes
- 30 seconds
- Costs
- Nothing, no email, nothing stored
Deliverability is decided before you write a word.
Most founders find out their sending setup is broken from the results: replies stop, and by then the domain has a reputation to repair. These checks are the part you can verify in advance, so I run them on every sending domain before warmup starts. They're step three of the Signal-to-Reply method, the infrastructure step, and the one that decides whether everything after it counts at all.
SPF says which servers may send as you, DKIM proves a message wasn't changed on the way, and DMARC tells receivers what to do when either fails. The two failures worth checking for aren't missing records. They're a second SPF record added when someone connected a new tool, which silently voids both, and an SPF record that grew one include too many and now costs more than 10 lookups. Both look fine in a DNS panel, and both fail every message.
The rule this tool is strictest about isn't technical: cold email goes out from a separate domain, never from the one your company runs on. That one decision turns a deliverability mistake from a company problem into a campaign problem. The full setup, with the daily cap I run per domain and the mistakes that got my own domains listed, is in the cold email domain setup guide.
A clean result here is necessary, not sufficient. Across 12,973 delivered cold emails we logged a 2.07% reply rate, and that was from domains that passed all of this. What moves that number is the list and the timing, which is what the cold outreach benchmarks are about.
Questions people ask
What does this checker look at?
Six things, all read from public DNS. Whether the domain has MX records, so replies can land. Whether it has exactly one SPF record, how it ends, and how many DNS lookups it costs once every include is followed, because receivers stop counting at 10 and fail the message. Whether a DKIM key is published at the selectors the common providers use, or at one you enter. Whether there's a DMARC record and what its policy asks receivers to do. Whether the domain ending is one filters trust less. And whether you're about to send cold email from the domain your company actually runs on.
Why not send cold email from my main domain?
Because a reputation problem doesn't stay in the cold campaign. If prospects mark you as spam or a list bounces badly, the domain gets marked down, and the domain is shared by your invoices, your proposals and your replies to real customers. A separate sending domain costs a few euros a year and keeps the damage contained. Every outbound engine I run sends from separate domains for exactly this reason.
Everything passes. Why is my email still landing in spam?
Because DNS is the entry ticket, not the result. The rest is behaviour: a new domain that sends before it's warmed up, too many sends per domain per day (the systems I build cap at roughly 25), a list with unverified addresses (a bounce rate around 6% is enough to sink a domain), and copy that reads like a template every other sender uses. This tool can't see any of that. It tells you the foundation is sound, so when results are poor you know to look at volume, list and copy instead.
Does it check blocklists?
No, on purpose. The blocklist that matters most, Spamhaus, refuses lookups that come through public DNS resolvers, which is what a browser tool has to use. A checker that queried it this way would tell you you're clean when it simply wasn't allowed to ask. Check Spamhaus directly on their own site instead.
Is my domain stored anywhere?
No. Your browser asks Google's public DNS service (dns.google) for the records and does the evaluation itself. Nothing is sent to us, there's no email gate, and closing the tab clears it.
Rather not run the infrastructure yourself?
Domains, warmup, per-domain caps, verification and reply routing are the boring half of outbound, and the half that decides if the other half works. I run it for B2B founders every week.