Guide
How to warm up a new domain for cold email
Short answer
Authenticate the domain first, then let each new mailbox build a sending history for a few weeks with low, gradually rising volume before any cold campaign, and keep a warm-up running alongside. Increase cold volume only while bounces and complaints stay low.
In short
- A new domain and mailbox have no reputation; mailbox providers are cautious with them.
- Authentication (SPF, DKIM, DMARC) comes before the first message.
- Warm-up means low, gradually increasing volume and real engagement over several weeks.
- Clean, verified lists matter as much as warm-up: bounces undo it quickly.
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Step by step
- Buy a secondary domain close to your brand and redirect its website to your main site.
- Set up SPF, DKIM and DMARC before sending anything. See the deliverability checklist.
- Create a small number of mailboxes on the domain with real names, photos and signatures.
- Turn on automated warm-up in your sending tool (Instantly and Smartlead include it) and let it run for a few weeks.
- Start cold sending at a low daily volume per mailbox and raise it gradually.
- Watch bounce rate, complaints and the warm-up score, and slow down at the first warning.
Mistakes that undo warm-up
- Sending to an unverified list: a high bounce rate in the first weeks is the fastest way to lose a new domain.
- Jumping from warm-up straight to full volume.
- Using the main company domain, so a problem reaches your everyday email.
- Links, attachments and tracking pixels in the very first cold emails.
How TechSales helps
Warm-up itself runs in Instantly or Smartlead. TechSales reads each Instantly mailbox's warm-up score and bounce rate every six hours (watch below 80, at risk below 60), counts slow-ramp mailboxes at what they can send now, and verifies every list before it reaches the sending tool. See Reports.
Frequently asked questions
- How long does warm-up take?
- Usually a few weeks before cold sending, with volume rising gradually after that. The right pace depends on the domain, the provider and how clean your lists are.
- Do I need warm-up if I use an old domain?
- An established domain has a history, but a mailbox that suddenly starts sending cold email still benefits from a gradual ramp.
- Does warm-up keep running during campaigns?
- Most teams keep it running alongside cold sending; sending tools allow both at once.
Sources
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