Email deliverability is the ability of your emails to reach the intended recipient’s inbox, not their spam folder or get blocked entirely. It’s not just about sending messages—it’s about ensuring they arrive, are seen, and are trusted by the recipient’s email provider. Poor deliverability can mean missed opportunities, lost sales, or broken customer communication, especially for businesses relying on regular email outreach.

Many factors influence whether an email gets through: sender reputation, email content, authentication setup (like SPF, DKIM, DMARC), list hygiene, and how recipients interact with your messages. If your emails are consistently marked as spam, bounced, or filtered out, the underlying issue is often one or more of these technical or behavioral signals. Even legitimate messages can fail to arrive if authentication is misconfigured, lists are outdated, or content triggers spam filters.

This hub covers practical steps and proven best practices to keep your emails in the inbox. You’ll learn how to verify your email setup, maintain clean and active lists, detect invalid or fake addresses, and respond to deliverability issues before they impact your campaigns. Whether you're managing newsletters, transactional messages, or targeted promotions, the principles here apply across industries—from law firms and accounting teams to online stores, coaching services, and healthcare providers.

What you'll find in this hub

  • How to verify and fix email authentication records like MX, SPF, DKIM, and DMARC
  • Practical methods for cleaning outdated or invalid email addresses from your list
  • How to identify and remove fake or non-human email addresses in forms and sign-ups
  • Strategies for maintaining deliverability during list growth or seasonal campaigns
  • Common causes of spam filtering and how to avoid triggering spam score detectors
  • Diagnosing and responding to deliverability drops or sudden email rejection rates

Start here

Browse all 48 articles in Email deliverability fundamentals and best practices →

Put it to work

See how your own emails score: run a deliverability test with MailTester.