Email Warmup

Email warmup is the process of gradually increasing the sending volume from a new email domain and inbox to establish positive sender reputation with email providers (Google, Microsoft, etc.) before launching cold outreach campaigns.

New email accounts are unknown to email providers. Sending hundreds of cold emails from a brand-new inbox immediately looks like spam behavior — because it is the same pattern as actual spammers. Warmup mimics organic email activity, slowly building the domain's credibility.

A typical warmup process: - Week 1: 5–10 emails/day, all replied to within the warmup pool - Week 2: 15–25 emails/day, maintaining high open + reply rates - Week 3–4: 30–50 emails/day, mixing warmup with initial real sends - Month 2+: Full send volume (50–80 emails/inbox/day)

Smartlead includes a built-in warmup pool — a private network of real inboxes that automatically engage with your outgoing warmup emails. This continuously rebuilds reputation even as you run live campaigns, making it the most reliable warmup system in the market for agencies.