Deliverability
Deliverability guides and product notes — no filler.
Why agencies can't skip blacklist monitoring
For agencies, a client's blacklisting becomes your problem. Why agency blacklist risk is multiplied, and how monitoring protects clients and your book.
How to check if your domain or IP is blacklisted
How to check if your domain or IP is on an email blacklist: which lists to look up, the free tools to use, and how to tell an emergency from a false alarm.
Emails going to spam in Outlook: the causes and fixes
Emails going to spam in Outlook? How Microsoft's reputation filtering works, plus SNDS, JMRP, and the fixes that move Office 365 mail to the inbox.
How to set up DMARC: the safe, step-by-step rollout
How to set up DMARC the safe way: publish the TXT record at p=none, read the aggregate reports, fix SPF and DKIM alignment, then enforce with reject.
One-click unsubscribe: the header pair Google now requires
One-click unsubscribe is the List-Unsubscribe header pair (RFC 8058) Google and Yahoo require on bulk mail. What it is, why it matters, and how to add it.
Spam complaint rate: the number that decides deliverability
Your spam complaint rate is complaints divided by delivered mail. Learn the 0.3% limit, the 0.1% target, and how to measure and reduce complaints.
Spam trigger words: the myth vs what filters weigh
Spam trigger words are mostly a myth: modern filters weigh reputation, authentication and list quality far more than any word in your copy.
The Barracuda blacklist (BRBL), explained and delisted
The Barracuda blacklist (BRBL) lists IPs with poor sending reputation. How to check, request free removal, and stay off it for good.
Proofpoint Dynamic Reputation and why enterprise mail gets blocked
Proofpoint Dynamic Reputation (PDR) blocks mail only to enterprise inboxes. How the Proofpoint blacklist works, and how to check and fix it.
Cold email deliverability: how to reach the inbox
Cold email deliverability is hard: no engagement and dirty lists. The levers that get cold outreach to the inbox — starting with verification.
SpamCop blacklist: how it lists and self-clears
The SpamCop blacklist (SCBL) lists sending IPs from spam reports and traps, then expires on its own. How it works, how to check, and how to get off.
The UCEPROTECT blacklist and its three levels, explained
How the UCEPROTECT blacklist's three levels work, why you can be listed through no fault of your own, the free-wait vs paid-express debate, and more.