What is Email Deliverability?
Email deliverability is the ability to successfully deliver emails to recipients' inboxes. Learn the fundamentals and best practices.
Understanding Email Deliverability
Email deliverability refers to the rate at which your emails successfully reach your recipients' inboxes. It's not just about whether an email was "delivered" (accepted by the receiving mail server), but whether it actually made it to the inbox rather than spam or being blocked entirely.
The three main outcomes for an email are:
- Inbox: Email arrives in the primary inbox (best outcome)
- Spam/Junk: Email is filtered to spam folder
- Blocked: Email is rejected entirely by the receiving server
The Four Pillars of Deliverability
1. Authentication (SPF, DKIM, DMARC)
Email authentication protocols prove that emails actually come from your domain and haven't been tampered with. Modern mailbox providers require proper authentication.
- SPF: Specifies which servers can send email for your domain
- DKIM: Cryptographically signs emails to prevent tampering
- DMARC: Tells receivers what to do with unauthenticated emails
2. Reputation
Your sending IP address and domain build reputation over time based on engagement rates, spam complaints, and bounce rates. Poor reputation leads to spam folder placement or blocks.
3. Content Quality
Email content is analyzed for spam characteristics including excessive links, misleading subject lines, poor HTML quality, and suspicious attachments. Clean, professional content performs better.
4. Engagement
High open rates, click rates, and low spam complaint rates signal to mailbox providers that recipients want your emails. Send to engaged subscribers and remove inactive ones regularly.
Common Deliverability Problems
- Missing or incorrect authentication: No SPF/DKIM/DMARC records or misconfigured settings
- Blocklist listings: IP or domain appears on spam blocklists
- Poor engagement: Low open rates or high spam complaint rates
- Bad list hygiene: Sending to purchased lists or old, inactive contacts
- Volume spikes: Suddenly sending much more email than usual
- Compliance violations: Not following CAN-SPAM, GDPR, or other regulations
How InboxReadyCheck Helps
Our platform helps you identify and fix deliverability issues across all four pillars:
- Validate SPF, DKIM, and DMARC authentication
- Check IP/domain reputation and blocklist status
- Analyze email content for spam characteristics
- Test inbox placement with real mailboxes (seed testing)
- Monitor infrastructure uptime and DNS health
- Verify compliance with email regulations
Next Steps
Now that you understand the basics, start improving your deliverability: