Cold email deliverability

Never send from your primary domain. Register two to four lookalike domains, point them at the main site with a redirect, and treat each as a disposable sending asset. Two mailboxes per domain is the ceiling we use — more mailboxes on one domain concentrates risk and gives you nothing back in volume.

All three records go in before warmup starts, not after. SPF authorises your sending provider, DKIM signs the message, DMARC tells receiving servers what to do when a check fails. Start DMARC on p=none with reporting on, read two weeks of reports, then move to quarantine once traffic looks clean.

Weeks one and two run automated warmup only. From week three, ramp real sends from roughly ten per mailbox per day toward a ceiling of thirty, adding a handful each day. Keep warmup running underneath live campaigns permanently — it's the baseline of positive engagement that carries a mailbox through a bad week.

Verify every address before it enters a sequence, and drop catch-all domains into a separate lower-volume track. A bounce rate above 3% is a reputation event, not a data problem — pause sending, re-verify, and resume at half the volume.

Plain text, no tracking pixels, no images, at most one link and only after the first reply where possible. Keep it short enough to read on a phone without scrolling. Filters read formatting density and link ratio far more aggressively than they read individual words.

Check placement weekly with seed testing, and watch reply rate as the real health signal — it falls before bounce rates move. If a mailbox degrades, pull it from rotation for two weeks, let warmup run alone, and reintroduce it at the bottom of the ramp.