Email deliverability check
Find out why your email lands in spam — SPF, DKIM, DMARC and MX, in one look.
The three records that decide whether your mail arrives
SPF lists the servers allowed to send mail as you. DKIM signs each message so the receiver can prove nothing was altered in transit. DMARC ties the two together and tells receivers what to do when they disagree with the From address — and where to send the reports.
Miss any of them and your mail is judged on reputation alone. Miss all three and a forger can send invoices in your name to your own customers, and nothing will stop them.
Why this got stricter
Gmail and Yahoo now expect anyone sending in volume to publish all three, authenticate properly, and keep complaints low. What was best practice for years is now the entry requirement, and domains that ignored it are the ones suddenly landing in spam without having changed anything.
The commonest cause of a sudden deliverability problem is not a blacklist. It is an SPF record that quietly went over the ten-lookup limit when somebody added one more service to it, at which point receivers treat the whole record as broken.
What this check cannot see
DKIM selectors are not discoverable. There is no way to ask a domain which selector it uses, so this tool tries fifteen common names — the ones Google, Microsoft, Zoho and the major senders use. A "not found" means none of those answered, not that you definitely have no key.
Nor can it see your sending reputation, your bounce rate or whether your content reads like spam. Those matter too. This check covers the part that is pure configuration, which is the part you can fix in an afternoon.