Free SPF, DKIM, DMARC & MX checker.
Run a live DNS lookup on any domain's SPF, DKIM, DMARC, and MX records and see in seconds which ones Gmail and Outlook will trust. No signup, and unlike inbox-placement testers, no test email to send.
What SPF, DKIM, DMARC, and MX actually check
SPF (Sender Policy Framework)
Lists which mail servers are allowed to send email on behalf of your domain. Without it, a receiving server has no way to confirm your ESP or SMTP relay is authorized to send as you, which makes spam-folder placement or outright rejection more likely.
DKIM (DomainKeys Identified Mail)
Attaches a cryptographic signature to every outgoing message so the receiving server can verify it wasn't altered in transit and genuinely originated from your domain's mail system.
DMARC (Domain-based Message Authentication, Reporting & Conformance)
Tells receiving servers what to do when a message fails SPF or DKIM — quarantine it, reject it, or let it through anyway — and where to send reports about who is currently sending mail as your domain.
MX (Mail Exchange)
Points to the servers responsible for receiving mail for your domain. A missing or misconfigured MX record can block incoming replies even when your outbound sending setup is otherwise fine.
Why a DNS lookup instead of a test email
Most "deliverability checkers" work by having you send a real email to a seed address, then grading whatever arrives. That's useful for catching spam-trigger words or a bad sending IP, but it says nothing about whether your authentication records are configured correctly, and it requires an extra step every time you want to re-check.
This tool skips that: enter a domain, and it queries the SPF, DKIM, DMARC, and MX DNS records directly, the same way Gmail and Outlook do at the moment of delivery. The trade-off is honesty, not magic — a DNS lookup can't give you a spam score or an inbox-placement percentage. Use this one first to rule authentication in or out as the cause, then pair it with a send-based tester if you need placement data too.
Passing all four checks is necessary but not sufficient for inbox placement — sender reputation and domain age matter just as much, which is why Warmerly pairs daily authentication monitoring with automated warmup instead of treating a passing DNS check as the finish line.
Frequently asked questions
What does this tool check?
It looks up your domain's SPF, DKIM, DMARC, and MX DNS records and tells you whether each one passes, is missing, or has an error — the same checks that determine whether Gmail and Outlook trust your sending domain.
Is this free checker actually free?
Yes. There's no signup, no email required, and results are instant, though checks are rate-limited to prevent abuse.
Why did DKIM show as 'not found' when I have DKIM set up?
DKIM selectors are chosen by whoever set up your sending domain, and there's no public way to discover the exact selector without checking your sent mail headers. This tool checks the most common selectors used by major email providers and ESPs — if your provider uses a custom selector, it may not be detected here even though DKIM is correctly configured.
Why is my email still going to spam if SPF, DKIM, and DMARC all pass?
Authentication passing means receiving servers trust that a message really came from your domain — it doesn't guarantee inbox placement. Sender reputation, engagement history, content, and how new the domain is all factor in separately. A domain with perfect SPF, DKIM, and DMARC can still land in spam if it's brand new or sending too much volume too fast; that's what email warmup is for.
How long does a DNS record change take to show up in this checker?
Usually minutes to a few hours, depending on your DNS provider's TTL setting, though it can occasionally take up to 24-48 hours. If a fix isn't reflecting yet, wait for your TTL to expire and re-run the check.
Do I need SPF, DKIM, and DMARC if I only send from Gmail or Microsoft 365?
Yes, if you're sending from a custom domain ([email protected]) rather than a free @gmail.com or @outlook.com address. Google Workspace and Microsoft 365 don't add these DNS records to your domain automatically — you still have to configure them yourself.
What do I do if something fails?
Each failing check includes a plain-English note on what's missing. For a full walkthrough of deliverability fundamentals, see our deliverability guide.
More free tools
Want Warmerly to monitor this daily?
Warmerly checks SPF, DKIM, DMARC, and MX every day and alerts you the moment something breaks — plus automated warmup to build the reputation these records alone can't.