Domain Warmup
The process of gradually increasing email sending volume from a new domain to build sender reputation with email providers. Skip this step and your cold emails go straight to spam — no exceptions.
Domain Warmup Is the Price of Admission
A brand new domain has zero reputation with Gmail, Outlook, and Yahoo. Sending 500 cold emails on day one is like walking into a party where nobody knows you and shouting at everyone — you get thrown out immediately. Warmup establishes your domain as a legitimate sender before you ask it to perform.
The Warmup Process
Week 1: Send 10-20 emails per day using a warmup tool. These are automated exchanges between real inboxes that simulate normal email behavior — sending, receiving, opening, replying, and moving emails out of spam.
Week 2: Increase to 30-50 per day. Continue warmup tool activity alongside small batches of real outreach.
Week 3-4: Ramp to 50-100 per day. Monitor deliverability metrics closely. If open rates drop below 30%, slow down.
Tools and Automation
Services like Instantly, Warmup Inbox, and Lemwarm automate the warmup process. They maintain a network of real email accounts that interact with your domain, signaling to email providers that your domain sends legitimate email that people engage with.
Maintaining Reputation
Warmup is not a one-time activity. Continue running warmup alongside your real campaigns to maintain positive engagement signals. If you pause sending for more than a week, resume at lower volume. Sender reputation is earned slowly and lost quickly — treat it like a credit score.
Frequently Asked Questions
How long does domain warmup take?
Minimum 2-3 weeks for basic warmup. Four to six weeks for optimal sender reputation. During this time, start with 10-20 emails per day and gradually increase to your target volume. Use a warmup tool that sends and receives emails automatically to simulate real engagement patterns.
Should you use a separate domain for cold email?
Absolutely. Never send cold email from your primary company domain. If your cold email domain gets blacklisted, you do not want it affecting your transactional email, customer communications, or team email. Use a domain that is similar but distinct — if your company is acme.com, send from acme-mail.com or getacme.com.
