Email newsletter glossary
Plain-English explanations of the terms you run into when sending a newsletter.
- What is SPF? Sender Policy Framework explained simply
SPF lets a domain publish, in DNS, which servers may send its mail. Learn how SPF works, what it does not check, and what Gmail and Yahoo require.
- What is DKIM? Email signatures explained simply
DKIM lets a domain sign each message so receivers can verify it with a public key in DNS. Learn how it works, how it relates to DMARC, and what Gmail requires.
- What is DMARC? Email spoofing protection explained simply
DMARC ties SPF and DKIM to your visible From domain and tells receivers how to treat failing mail. Learn what p=none, quarantine and reject mean.
- What is double opt-in? Confirmed subscriptions explained
Double opt-in means new subscribers confirm their address via a link in a confirmation email. Learn how it works and why Google and Yahoo suggest it.
- What is a preheader? The preview text next to your subject line
A preheader is the preview text shown next to the subject line in the inbox. Learn what it does, how to write one, and why hiding it with CSS is risky.
- What is a hard bounce? Undeliverable email explained
A hard bounce is an email that cannot be delivered for a lasting reason, like a nonexistent address. Learn how it differs from a soft bounce and what to do.
- What is one-click unsubscribe? RFC 8058 explained simply
One-click unsubscribe lets people stop your emails with one inbox button. Learn the RFC 8058 headers, the DKIM rule, and what Gmail and Yahoo require.
- What is CAN-SPAM? The U.S. email law explained simply
CAN-SPAM is the U.S. law for commercial email. No prior consent is needed, but each message needs accurate headers, a postal address and a working opt-out.