How to Warm Up a New Email Domain for Cold Outreach

Starting cold email campaigns with a brand-new email domain without proper preparation is a recipe for spam folders, low deliverability, and poor engagement.

Domain warm-up is the process of gradually building trust with email providers to ensure your emails reach the inbox instead of being flagged as spam.

In this guide, we’ll cover how to safely and effectively warm up a new email domain for cold outreach in 2025.

Why Domain Warm-Up Matters

• Builds sender reputation: ISPs monitor sending behavior and engagement
• Prevents spam issues: Avoids being blacklisted or blocked
• Improves deliverability: Ensures cold emails reach your prospects’ inboxes
• Protects ROI: Increases response rates and conversion

Stat: Domains sent cold emails without warm-up can see 80–90% of emails land in spam.

Step-by-Step Guide to Warm Up a New Email Domain

Step 1: Set Up Your Domain Properly

• Use a domain dedicated to cold outreach (not your primary business domain)
• Set up proper DNS records:
  • SPF → verifies you can send emails from this domain
  • DKIM → ensures emails aren’t tampered with
  • DMARC → protects domain reputation

Step 2: Start Slowly

• Begin with small volumes of highly engaged emails (to friends, colleagues, or internal testers)
• Example schedule:
  • Week 1: 10–20 emails/day
  • Week 2: 30–50 emails/day
  • Gradually increase each week

Step 3: Send High-Quality Emails

• Focus on personalized, valuable emails
• Avoid sending mass, generic, or spammy messages early
• Include clear CTAs and relevant content

Step 4: Monitor Engagement Metrics

• Track opens, clicks, replies, and bounces
• High engagement signals to ISPs that your emails are legitimate
• Remove inactive or unengaged contacts

Step 5: Gradually Increase Volume

• Increase sending gradually over 4–6 weeks
• Maintain high engagement and low bounce rates
• Avoid sudden spikes that can trigger spam filters

Step 6: Use Email Warm-Up Tools

• Automate the warm-up process using tools like:
  • Mailflow
  • Warmup Inbox
  • Lemwarm (Lemlist)
• These tools help simulate natural email activity, improving domain reputation

Step 7: Keep Domain Hygiene

• Regularly check for blacklist status
• Maintain low bounce rates and remove invalid emails
• Keep a consistent sending schedule

Best Practices for Cold Outreach with a New Domain

• Don’t use your main business domain — risk to primary email is high
• Segment your audience and personalize emails
• Avoid spammy words and aggressive sales tactics early
• Track metrics and iterate — data-driven approach improves deliverability

Final Thoughts

Warming up a new email domain is critical for successful cold outreach. In 2025, following a structured, gradual warm-up strategy ensures:

• Higher deliverability
• Better response rates
• Protection of your domain’s reputation

💡 Start slow, send high-quality emails, monitor engagement, and gradually scale. Your cold outreach campaigns will perform far better with a warmed-up domain.