If clients keep telling you "your email went to spam", the cause is almost never the wording of your message. It's three DNS records most businesses have never heard of.
The problem they solve
Email's original design lets anyone send a message claiming to be from anyone. Spammers exploited that for decades, so mail providers now demand proof. Three records provide it.
SPF — the guest list
SPF (Sender Policy Framework) is a DNS record listing which servers are allowed to send email for your domain. When your message arrives, the receiving server checks: did this come from a server on the list? If you send through your hosting provider and a newsletter tool, both must be on the list — a common gap that silently breaks campaigns.
DKIM — the wax seal
DKIM (DomainKeys Identified Mail) adds a cryptographic signature to every outgoing message. The public key lives in your DNS; receiving servers use it to verify the message wasn't altered in transit and genuinely comes from your domain. No valid signature, no trust.
DMARC — the instructions
DMARC ties the two together and tells receiving servers what to do when a message fails: deliver anyway (p=none), quarantine it to spam, or reject it outright. It also sends you reports about who is sending mail claiming to be you — which is how many businesses discover impersonation attempts.
A sensible rollout: start with p=none to observe, then tighten to quarantine and eventually reject once you're sure all legitimate senders are covered.
The practical checklist
- List every service that sends email as your domain (hosting, CRM, newsletter tool, invoicing software).
- Ensure each is covered by SPF and signs with DKIM.
- Publish a DMARC record — even
p=nonestarts the reporting. - Test with any free mail-tester before and after.
Since Gmail and Yahoo tightened bulk-sender rules, these records went from "nice to have" to "your mail doesn't arrive without them."
We configure SPF, DKIM and DMARC for every email account we manage — if yours were set up years ago and never reviewed, an audit takes minutes and can rescue your deliverability.