Avoid the spam folder: an email deliverability checklist

Deliverability is whether your email reaches the inbox, not the spam folder. For business email it usually comes down to four things: authentication, reputation, content and monitoring. Use this checklist to cover them all.

1. Authentication (the foundation)

• SPF record published, listing every service that sends as your domain, and only one SPF record.
• DKIM signing enabled and the public key published.
• DMARC record published, starting at p=none and moving toward quarantine or reject.
• MX records point to your current provider, with no leftovers from old providers.
• Your “From” domain matches the domain you authenticate (alignment).

Our SPF, DKIM and DMARC guide explains each step.

2. Reputation

Mailbox providers track the reputation of your domain and of the servers that send for it.

• Your sending server’s IP is not on major blocklists such as Spamhaus or SpamCop.
• You send to people who expect to hear from you. Purchased lists destroy reputation.
• You keep complaint rates very low. If people mark you as spam, providers notice.
• You remove addresses that bounce.
• New domains start with modest volume and grow gradually.

3. Content

Content filters matter less than authentication and reputation, but they still count.

• Clear, honest subject lines. No ALL CAPS or excessive punctuation!!!
• A reasonable text-to-image balance. Avoid emails that are a single large image.
• Links point to reputable domains, ideally your own. Avoid URL shorteners.
• A plain-text version accompanies HTML (good providers do this for you).
• A real signature with your name, company and contact details.
• Attachments are only what’s needed; large or unusual file types can trigger filters.

4. Sending habits

• Send one-to-one business email from a business email service, and newsletters from a dedicated newsletter tool, ideally from a subdomain.
• Avoid sudden spikes in volume.
• Reply to replies. Two-way conversations are a strong positive signal.

5. Monitoring

Deliverability isn’t “set and forget.” DNS records get deleted during website migrations, a teammate adds a new tool without updating SPF, or a shared IP lands on a blocklist.

• Check authentication results in a received message (“Show original” in Gmail).
• Review DMARC aggregate reports occasionally.
• Monitor MX, SPF, DKIM, DMARC and blocklists continuously.

VoraMail’s domain health monitor does the last item for you: it checks every few hours and emails you when a domain goes from healthy to failing, with the exact record that broke.

Quick troubleshooting

Work through the list once, then keep monitoring. That’s most of what it takes to stay out of the spam folder.