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Email Deliverability Checklist

Interactive audit checklist covering email authentication, sending infrastructure, list hygiene, content best practices, and monitoring. Score your deliverability setup against 26 best practices.

About this tool

Only about 85% of legitimate marketing emails actually reach the inbox—the rest land in spam or get blocked entirely. That means if you're sending to 10,000 subscribers, roughly 1,500 might never see your email. This interactive checklist covers the 26 practices that separate senders with 98%+ inbox placement from those struggling to break 80%. Work through it systematically—each item you check off directly improves your deliverability.

The Authentication Trio: SPF, DKIM, and DMARC

Email authentication is non-negotiable in 2024+. You need all three: SPF tells receiving servers which IPs can send email for your domain. DKIM cryptographically signs each email so receivers can verify it hasn't been tampered with. DMARC ties them together with a policy that tells receivers what to do when authentication fails. Missing even one of these three means Gmail, Yahoo, and Outlook will treat your emails with suspicion. Use our generators (SPF, DKIM, DMARC) to set them up, then verify with the checkers.

List Hygiene: The Foundation of Reputation

Your sender reputation is only as good as your list. Validate every email at signup using real-time verification. Implement double opt-in for web forms—it reduces list size by 20-30% but virtually eliminates spam traps and fake signups. Remove hard bounces immediately after every campaign. Suppress addresses that soft-bounce 3+ times. Run a re-engagement campaign for subscribers who haven't opened in 90 days, then remove the non-responders. Never, ever buy or rent email lists.

Content Quality and Sending Patterns

Even with perfect authentication and a clean list, your content matters. Avoid common spam trigger words (use our spam word checker). Maintain a healthy text-to-image ratio—all-image emails get filtered aggressively. Keep your HTML clean and under 100KB. Send consistently—sudden spikes in volume trigger ISP scrutiny. If you're ramping up volume, use a warmup schedule to gradually increase sends over 4-8 weeks.

Ongoing Monitoring and Quick Response

Deliverability isn't a one-time setup—it's ongoing maintenance. Check your domain against blacklists weekly. Monitor your bounce rate after every campaign. Track your unsubscribe rate—Gmail's threshold is 0.3%, and exceeding it triggers filtering. Watch for sudden drops in open rates, which often signal deliverability issues before they become critical. Run this full checklist quarterly to catch drift.

Frequently Asked Questions

What is email deliverability?

Email deliverability is the percentage of your emails that actually reach the inbox (not spam or promotions tab). It depends on your sender reputation, authentication setup, list quality, content, and sending patterns. A good inbox placement rate is 95%+. The industry average hovers around 85%, meaning 15% of legitimate emails never reach the inbox.

What are the most important deliverability factors?

In order of impact: sender reputation (built from engagement rates and complaint history), email authentication (SPF, DKIM, DMARC all passing), list quality (low bounce rates, no spam traps), content quality (no spam triggers, proper formatting), and sending patterns (consistent volume, proper warmup). Fix authentication first—it's the easiest win and the most common gap.

How often should I audit my deliverability?

Run this full checklist quarterly. Check authentication records monthly (they can break when someone changes DNS settings). Monitor bounce rates and complaint rates after every campaign. Check blacklists weekly. If you see open rates drop by more than 20% suddenly, run an emergency audit—something likely broke.

What bounce rate will get me blacklisted?

Most blacklists trigger at sustained bounce rates above 5-10%, but ISPs start throttling well before that. Gmail and Outlook begin filtering more aggressively when your bounce rate consistently exceeds 2%. Hard bounce rates above 0.5% per campaign are a red flag. The key word is 'sustained'—one bad campaign won't blocklist you, but a pattern will.

Do I really need all three of SPF, DKIM, and DMARC?

Yes. Since Google and Yahoo's February 2024 requirements, all three are effectively mandatory for bulk senders. SPF alone was sufficient 5 years ago. Today, missing DKIM or DMARC means your emails are more likely to be filtered. Setting up all three takes about an hour and pays dividends for as long as you send email from that domain.

What's the fastest way to improve deliverability?

The fastest wins, in order: 1) Set up SPF, DKIM, and DMARC if missing (1 hour, immediate impact). 2) Remove all hard bounces from your list (10 minutes, immediate impact). 3) Run a list validation service on your entire list and remove invalids (1 hour, takes effect next send). 4) Add one-click unsubscribe headers (reduces spam complaints within days). These four steps alone can move you from 80% to 95%+ inbox placement.

How do I know if my emails are going to spam?

The clearest signal is a sudden, unexplained drop in open rates—if opens fall 30%+ without a content change, emails are being filtered. Seed testing services like GlockApps or Mail-Tester send your email to test accounts across providers and report where they land. You can also ask a few subscribers to check their spam folders. Monitor Google Postmaster Tools for Gmail-specific reputation data.

What is a spam trap and how do I avoid them?

Spam traps are email addresses operated by ISPs and blacklist operators to catch spammers. There are two types: recycled traps (old addresses that once belonged to real people but were abandoned and repurposed) and pristine traps (addresses that were never used by real people). You hit recycled traps by keeping stale addresses on your list. You hit pristine traps by buying lists. Double opt-in and regular list cleaning are your best defenses.

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