Email Deliverability
The percentage of your emails that actually reach the recipient's inbox rather than bouncing, landing in spam, or getting blocked by email providers.
Deliverability Is the Foundation Everything Else Sits On
You can write the perfect subject line, craft a compelling offer, and segment your list with surgical precision — none of it matters if your emails land in spam. Deliverability is the invisible infrastructure of email marketing. When it works, you never think about it. When it breaks, every metric in your dashboard collapses.
For SaaS companies running outbound sequences and lifecycle campaigns, deliverability is not a “set it and forget it” metric. Gmail, Microsoft, and Yahoo constantly update their filtering algorithms. What worked six months ago might be getting flagged today. The companies that maintain 98%+ deliverability are the ones actively monitoring and adjusting.
How Deliverability Is Determined
Email providers evaluate your messages on three levels:
| Level | What Is Checked | Impact |
|---|---|---|
| Infrastructure | SPF, DKIM, DMARC authentication | Pass/fail — missing = spam folder |
| Reputation | Sending domain and IP reputation scores | Low reputation = throttled or blocked |
| Content | Spam words, link density, image-to-text ratio | Triggers spam filters on individual emails |
Your sending reputation is built over time based on bounce rates, spam complaints, engagement rates, and sending patterns. Think of it like a credit score — easy to destroy, slow to rebuild.
How to Protect Your Deliverability
Start with authentication — SPF, DKIM, and DMARC should be configured on every sending domain (see our SPF/DKIM/DMARC glossary entry). Clean your list quarterly by removing hard bounces, inactive contacts, and spam traps. Send consistently — large spikes in volume trigger spam filters. Segment your sends so engaged contacts get more emails and disengaged contacts get fewer. And monitor your domain reputation through Google Postmaster Tools and Microsoft SNDS. If your spam rate exceeds 0.3% on Gmail, you are in the danger zone.
Frequently Asked Questions
What is a good email deliverability rate?
95%+ deliverability is the baseline for healthy sending. Top performers hit 98-99%. Below 90%, you have a serious problem — one in ten emails is not reaching the inbox, which means your campaigns are underperforming by at least 10% before anyone even sees your subject line. Monitor deliverability weekly, not monthly.
What kills email deliverability?
Five things destroy deliverability: sending to invalid or outdated email addresses (high bounce rate), getting marked as spam by recipients, sending too much volume too fast from a new domain, poor authentication (missing SPF, DKIM, DMARC), and using spam-trigger words excessively. Any one of these can tank your sender reputation within a week.
