TL;DR:
- Top deliverability factors: SPF / DKIM / DMARC setup, sender reputation, list hygiene, engagement metrics.
- Industry benchmark: 95%+ inbox rate. Below 90%: serious deliverability problem.
- Best for high deliverability: Beehiiv, ConvertKit, Klaviyo. Mailchimp deliverability has declined.
What Affects Email Deliverability?
| Factor | Impact |
|---|---|
| SPF / DKIM / DMARC setup | Critical (50%+ deliverability impact) |
| Sender reputation | High (built over months) |
| List hygiene | High (remove inactive subs) |
| Engagement (opens/clicks) | High (signals algorithm) |
| Spam complaints | Very high (1+ per 1K = trouble) |
| Email content (spam triggers) | Moderate |
| Frequency | Moderate (don't blast) |
Step 1 — Set Up SPF / DKIM / DMARC
- Authentication records in your DNS.
- Tells Gmail / Outlook your emails are legitimate.
- Email tool (Mailchimp / ConvertKit / etc.) provides setup instructions.
- Without these: 50%+ of emails go to spam.
Step 2 — Custom Sending Domain
- Use yourdomain.com email vs free email.
- Better deliverability + branding.
- Configure within email tool.
Step 3 — Warm Up New Sending Domain
For new domains:
- Send slowly first (50-100/day).
- Increase by 25-50% per week.
- Reach full volume over 4-8 weeks.
- Builds positive sender reputation.
Step 4 — List Hygiene
- Remove inactive subscribers (180+ days no opens).
- Re-engagement campaign before removal.
- Validate emails on signup (Kickbox, ZeroBounce).
- Don't email purchased lists.
Step 5 — Avoid Spam Triggers
- Avoid words: "free!!!" "limited time" excessive caps.
- Don't use shortened URLs (bit.ly).
- Avoid attachments > 1 MB.
- Maintain text-to-image ratio (mostly text).
- Include unsubscribe link.
- Plain text version available.
Step 6 — Monitor + Optimize
- Track open rate (target 25%+).
- Track click rate (target 3%+).
- Track spam complaint rate (target <0.1%).
- Use Postmaster tools (Gmail, Yahoo).
- Adjust based on metrics.
Email Tools by Deliverability
| Tool | Deliverability rating |
|---|---|
| Beehiiv | Excellent (98%+) |
| ConvertKit | Excellent (97%+) |
| Klaviyo | Excellent (97%+) |
| ActiveCampaign | Good (95%+) |
| Mailchimp | Declining (~85-90%) |
| Gmail / Outlook (SMTP) | Good but rate-limited |
Frequently Asked Questions
Why do my emails go to spam?
Most likely: SPF/DKIM/DMARC not set up, low engagement, sending too fast, spam-triggering content.
Best email service for deliverability?
Beehiiv + ConvertKit + Klaviyo. Mailchimp deliverability has declined.
How do I check my deliverability?
Use mail-tester.com. Check Gmail Postmaster tools. Monitor open + spam rates.
Should I remove inactive subscribers?
Yes — quarterly. Inactive subs hurt deliverability. Re-engagement campaign before removal.
Can I email purchased lists?
Don't — violates GDPR/CAN-SPAM + tanks deliverability. Build organically.
Key Takeaways
- Set up SPF / DKIM / DMARC (most important).
- Use custom sending domain.
- List hygiene: remove inactives quarterly.
- Monitor open / click / spam rates.
- Best tools: Beehiiv, ConvertKit, Klaviyo (avoid Mailchimp at scale).
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