Email deliverability checklist for cold outreach
Your open rate is not deliverability. If you do not nail the fundamentals below, nothing downstream matters.
- Send from a subdomain, never from your primary domain.
- SPF + DKIM + DMARC are not optional. All three must be aligned.
- Every address should be SMTP-verified before it hits a sequence.
- If reply rate drops suddenly, deliverability broke 48 hours earlier, check postmaster dashboards.
Domain & auth (SPF/DKIM/DMARC)
Without SPF, DKIM, and DMARC aligned, you are flagged at the gateway. Send from a subdomain (e.g. go.yourbrand.com), not your primary domain, so any reputation damage is contained.
- SPF record: list every sending IP/provider
- DKIM: 2048-bit keys, one per selector
- DMARC: start at p=none; monitor aggregate reports; ratchet to quarantine then reject
- BIMI for brand logos in Gmail (once DMARC is at quarantine)
Warming a new mailbox
Do not send 500 cold emails from a brand-new inbox. Warm for 14-21 days: a handful of personal exchanges per day, ramping gradually, opening and replying to fake conversations inside the warming network.
List hygiene
Bounce rate above 3% is a death sentence. Leadzy verifies every email at enrichment and scores deliverability, catch-all domains are flagged so you can decide risk per address.
Content heuristics
Short and plain beats long and pretty. Avoid image-heavy bodies, links above text, and spam-trigger language. Read your email aloud, if it sounds like marketing, rewrite it.
Monitoring
Watch your Postmaster Tools dashboard, your bounce breakdown (hard vs soft), and your reply rate trend. A reply rate cliff usually precedes a deliverability issue by 48 hours.
"Deliverability is not the last mile, it is the whole road. Everything upstream depends on it."