Email Deliverability Tips: Keep Your Emails Out of Spam
Perfect email copy doesn't matter if your emails land in spam. Deliverability starts with authentication (SPF, DKIM, DMARC), list hygiene, and sending practices. Get these right and you'll hit the inbox 95%+ of the time.
The 3 Pillars of Email Deliverability
Pillar 1: Authentication (SPF, DKIM, DMARC)
Email authentication proves your emails really come from your domain:
Setup Checklist:
- SPF: Add SPF record to your domain DNS. Takes 5 min. Tells ISPs which servers can send from your domain.
- DKIM: Generate DKIM key from your email provider. Add to DNS. Also 5 min. Digitally signs each email.
- DMARC: Create DMARC policy. Tells ISPs what to do if SPF/DKIM fails (reject, quarantine, or allow). Most important for brand protection.
Total time to set up all 3: 30 minutes. Critical foundation.
Pillar 2: List Hygiene
A clean list = better sender reputation = inbox placement.
| List Quality Issue | Impact | Fix |
|---|---|---|
| Hard Bounces | Email doesn't exist. Damages sender rep. | Verify list with ZeroBounce, remove invalid emails |
| Inactive Emails | No engagement in 1+ year. Spam folder signal. | Segment and don't email them. Or re-engagement campaign first. |
| High Complaint Rate | > 0.1% mark as spam = ISP blocks future emails. | Remove complainers immediately. Check subject lines (too salesy?). |
| Bought Lists | Spam folder magnet. Low engagement = poor sender rep. | Build lists organically. Use verified data sources. |
Pillar 3: Sending Best Practices
Warm Up New Domains
Don't send 1,000 emails from a brand-new domain on day 1. ISPs see this as spam. Warm up instead:
- Day 1-3: Send 50-100 emails/day
- Day 4-7: Send 200-300 emails/day
- Day 8-14: Send 500-1000 emails/day
- Day 15+: Send as much as you want
Space Out Sends
Don't send 500 emails in 5 minutes. Space them out:
- Good: 50-100 emails per hour
- Better: 20-30 emails per hour
- Best: 1-2 second delay between emails (mimics human sending)
Use Real "From" Addresses
"[email protected]" kills open rates (20-30% lower). Use real team member emails.
- Good: [email protected] (Sarah Johnson, VP Sales)
- Bad: [email protected]
- Also bad: [email protected] (generic, looks automated)
Avoid Spam Trigger Words
Subject lines with these words get flagged:
- FREE, URGENT, LIMITED TIME, ACT NOW, CALL NOW, Click here, Buy now, $$$, Limited slots
Use them only if genuinely relevant. Better: "Quick question about X" or "Sarah, noticed you hired for sales"
Always Include Unsubscribe Link
Legal requirement (CAN-SPAM). Also protects sender reputation. People who want to opt out will mark as spam if no unsubscribe link.
Don't Use Purchased Sender Reputation
Never send from someone else's domain or use a shared sending IP (unless using legitimate ESP). Build your own reputation.
Monitoring Your Sender Reputation
Check these metrics weekly:
| Metric | Healthy Range | If Below Range |
|---|---|---|
| Bounce Rate | < 2% | Verify list, remove invalid emails |
| Complaint Rate | < 0.1% | Check subject lines, reduce frequency, improve relevance |
| Unsubscribe Rate | < 0.5% | Normal. Healthy. You're finding uninterested people. |
| Emails to Spam | < 1% | Check authentication, list quality, subject lines |
Tools to Improve Deliverability
- MXToolbox: Check SPF, DKIM, DMARC records for errors
- ZeroBounce: Verify email list before sending (removes 10-20% of invalid emails)
- MailerCheck: Test email deliverability for specific inboxes
- 250ok: Monitor sender reputation in real-time
- Google Postmaster Tools: Monitor Gmail inbox placement