Email Deliverability Checklist (Interactive)

A DNS TXT record starting with v=spf1 lists the servers allowed to send for your domain. Look it up in any DNS checker and send a test to see SPF pass.

Your sending tool signs each message with a private key and publishes the public key in DNS. Open a received message and confirm a DKIM-Signature header with a d= matching your domain.

A _dmarc TXT record tells receivers what to do when SPF or DKIM fails. Start at p=none to collect reports, then move to quarantine or reject once legitimate mail passes.

DMARC passes when the visible From domain matches the authenticated domain. Sending through a tool that rewrites the From address breaks alignment.

Each sending IP should have a PTR record that resolves back to a hostname that resolves forward to the same IP. Most sending tools handle this; self-hosted mail does not.

Transport encryption is expected by major providers and protects the message in transit. Managed senders turn this on by default.

Opt-in, a real prior relationship, or a legitimate business reason. Purchased or scraped lists produce complaints, and complaints destroy reputation.

Syntax-check every address, and for cold outreach verify deliverability with a validation tool. This is the single biggest lever on bounce rate.

A hard bounce never becomes deliverable. Remove those addresses from the list the same day and stop retrying them.

One address, one send per campaign. Duplicates read as bulk mail and add complaints without adding reach.

If someone has ignored a year of mail, they are more likely to report the next one as spam. Send a re-engagement message, then remove non-openers.

Start with a small daily volume and grow over several weeks. A brand-new domain that suddenly sends thousands of messages looks like a compromised account.

Steady patterns beat spikes. Sudden tenfold spikes from a domain with no history are filtered first.

Marketing mail needs a clear opt-out. At bulk volume, Gmail and Yahoo require one-click unsubscribe that processes requests within two days.

Multipart messages with a text part are friendlier to filters and screen readers, and they render in clients that block HTML.

Engagement is the strongest long-term signal. Ask for one clear action, reply to replies, and keep the list to people who want the mail.

Google asks bulk senders to stay under 0.3 percent and recommends under 0.1 percent. Get the number from your sending tool or Google Postmaster Tools.

Anything above roughly 2 percent on an opt-in list means the list has gone stale. Investigate before the next send.

Aggregate reports show who sends as your domain and whether it passes. They are how you catch a misconfigured tool before receivers do.

Check Spamhaus and Google Postmaster Tools periodically. If your domain appears, stop sending, fix the cause, and request removal.

Seed or placement testing shows whether mail lands in the inbox, the promotions tab, or spam before a campaign goes to the whole list.