Free tool
Free mail domain checker
Whether a domain can receive mail, who hosts it, and how its authentication looks.
How this works
This tool reports the domain-level signals that decide whether mail to or from a domain is trusted: whether it accepts mail at all, which provider handles it, and whether its authentication records are published.
It deliberately does not query public DNSBLs on your behalf. Those lists rate-limit and, in several cases, block queries from shared infrastructure — a free web tool that hammers them returns unreliable answers and eventually gets everyone using it blocked. We monitor our own sending IPs against them continuously, which is the case that actually affects the results you get from us.
A domain missing SPF or DMARC is not blocklisted, but it is far more likely to have its mail filtered, and it is trivially spoofable by anyone who cares to.
Questions, answered.
How do I check if my domain is blacklisted?
Domain-level blocklists are rare; the meaningful ones list sending IP addresses. Ask your mail provider which IPs you send from and check those against Spamhaus and Barracuda directly. This tool reports the domain-level signals instead — MX, SPF and DMARC — which are the parts you can actually change.
Why is my email going to spam?
Most often list quality rather than blocklisting. Sending to addresses that bounce, to spam traps, or to people who never opted in damages reputation faster than any technical misconfiguration. Verify a list before you send to it.
Does a missing DMARC record hurt deliverability?
Increasingly, yes. Google and Yahoo both require authentication for bulk senders, and a domain with no DMARC record is easier to spoof — which damages the domain's reputation over time even when you did nothing wrong.
What is a spam trap?
An address that exists only to catch senders who did not get permission — either a never-used address, or a long-abandoned one recycled by the provider. Hitting one is disproportionately damaging, and list verification is the main defence.