You can write the perfect cold email, but if it lands in spam, it's worthless. Email deliverability is the foundation of any successful cold email campaign. Here's everything you need to know to consistently land in the primary inbox.

Set Up Your Domain Correctly First

Never send cold emails from your main business domain — you risk blacklisting it. Instead, buy a similar domain (e.g., if your domain is nexliot.com, use nexliotmarketing.com or nexliot.co) and use it exclusively for outreach. Configure these DNS records:

  • SPF: Authorizes your email sending servers
  • DKIM: Cryptographically signs your emails
  • DMARC: Tells receiving servers what to do with failed checks
  • Custom tracking domain: For open and click tracking
⚠️ Critical: Without proper SPF, DKIM, and DMARC records, 40–60% of your emails will land in spam regardless of content quality.

Warm Up Your Domain (Non-Negotiable)

A new email domain needs 4–6 weeks of warming before sending cold outreach at scale. Use tools like Instantly's warmup feature or Lemwarm to automatically send and reply to warmup emails. Start at 10 emails/day and increase by 5–10 daily until reaching 50–100/day.

Sending Limits by Account Age

  • Week 1–2: Maximum 20 emails/day per inbox
  • Week 3–4: Up to 40 emails/day per inbox
  • Month 2+: Up to 100 emails/day per inbox
  • Scale: Use multiple inboxes (3–5) on separate domains for higher volume

Content Best Practices for Inbox Placement

Keep text-to-link ratio high (max 1–2 links per email). Avoid spam trigger words. Personalize at least 2 elements per email. Keep emails under 150 words for initial outreach. Never use HTML-heavy templates for cold outreach — plain text performs significantly better.

📊 Benchmark: With proper domain setup and warming, our clients achieve average inbox placement rates of 94%+ compared to the industry average of 79%.