Email Deliverability Guide: Ensuring Your Emails Land, Not Spam

You can have the world's best cold email copy and an impeccably targeted list — and if your emails land in spam, you have nothing. Email deliverability is the unglamorous foundation of every effective outbound program.

The Deliverability Fundamentals

DNS Configuration

Three DNS records are non-negotiable:

• SPF (Sender Policy Framework): Authorizes which servers can send email on behalf of your domain
• DKIM (DomainKeys Identified Mail): Cryptographic signature that proves email hasn't been tampered with
• DMARC (Domain-based Message Authentication): Policy that tells receiving servers what to do with emails that fail SPF or DKIM checks

All three must be correctly configured before sending a single outbound email. Use mail-tester.com to verify your setup.

Domain Warm-Up

New domains (and new domains you're using for outbound to protect your main domain) must be warmed up before heavy sending. Week 1: 10-20 emails/day. Week 2: 30-50. Week 3: 50-100. Week 4+: ramp to full volume. Jumping straight to 500 emails/day from a new domain will trigger spam filters immediately.

Inbox Placement vs Spam Placement

Monitor your inbox placement rate (not just open rate — opens only happen from the inbox). Tools like GlockApps and Mail Genius test your emails against major providers before sending. Run tests weekly when actively sending outbound.

Sending Behavior

• Keep daily send volume per inbox under 50-100 emails
• Use multiple inboxes in rotation (inbox rotation) for higher volume
• Maintain bounce rates under 2% — high bounces are a major spam signal
• Monitor spam complaint rates — above 0.1% starts hurting deliverability
• Verify email addresses before sending (NeverBounce, ZeroBounce)

Deliverability isn't a set-and-forget task. Monitor it weekly, react to degradation immediately, and rotate domains and inboxes proactively. The best copy in the world is worthless from the spam folder.