Why your email goes to spam, and the four records that fix it

Your email is not in spam because you used the word "free". It is in spam because Gmail cannot prove the message is really from your domain. That is a DNS problem, and DNS problems have exact answers.

The inbox is an identity check

When mail arrives, Gmail and Outlook ask three questions. Is this server allowed to send for this domain? Was the message signed by the domain and unchanged in transit? Does the domain say what to do when a message fails those checks? Those are SPF, DKIM, and DMARC. Mail that answers all three lands. Mail that does not gets the benefit of the doubt for a while, then stops getting it.

The four records

When you add a sending domain in Mule Mail, it generates these for you:

• SPF: one TXT record listing who may send for the domain.
• DKIM: a CNAME (or three) that publishes the public key your mail is signed with.
• DMARC: a TXT record at _dmarc that sets the policy and an address for reports.
• Return-path: a CNAME so bounces come back to the sender, not the recipient.

There is no fifth secret. People who sell "deliverability consulting" are mostly selling the patience to set these up correctly.

Use a subdomain

Send from mail.yourcompany.com, not yourcompany.com. A subdomain isolates your marketing reputation from the mail your accountant sends from Outlook. If a campaign goes badly, your invoices still arrive.

Start DMARC soft, then tighten

Set DMARC to p=none first and read the reports for a week. Once your real mail passes, move to p=quarantine, then p=reject. Mule Mail has a stepper for exactly this. Skipping straight to reject before your mail aligns is how people accidentally send their own newsletter to their own spam folder.

Set the four records. Verify them. Then worry about the subject line, which matters far less than the internet told you it does.