Cold email deliverability: setup checklist for B2B outbound
tech2gtm · · Updated · 7 min
Short answer
Good cold email deliverability comes from separate sending domains, correct SPF, DKIM and DMARC records, a two to four week warmup, low daily volume per inbox (around 30 to 50), verified contact data and plain-text messages that people actually reply to.
01
Protect your main domain
Never send cold email from your company's main domain. Register two or three similar domains and redirect them to your site.
Each domain gets two or three inboxes.
02
Authentication records
SPF lists which servers may send for the domain. DKIM signs messages so they can't be altered. DMARC tells receivers what to do when checks fail; start with p=none and monitor.
Check all three with a free DNS tool before the first send.
03
Volume and data hygiene
Warm up inboxes for two to four weeks. Keep each inbox to roughly 30 to 50 sends a day, spread across hours.
Verify every email before sending; bounce rates above 2 to 3 percent damage reputation quickly.
04
Implementation check
Cold email deliverability is an infrastructure task, not a copywriting shortcut. Check sending-domain authentication, inbox limits and monitoring before launching sequences; authentication alone does not guarantee inbox placement.
From practice: how our builds set this up
In the 30-day build, infrastructure comes before any message is written: dedicated sending domains with warmup, SPF, DKIM and DMARC, and inbox rotation, connected to HubSpot pipelines.
Technical takeaway: never send cold email from your primary domain, and keep daily volume per inbox low and steady while new domains warm up.
Frequently asked questions
How long does warmup take?
Two to four weeks is typical before sending at full planned volume.
Do links and images hurt deliverability?
In first-touch emails, yes, they can. Plain text with no links or one link performs most reliably.