Best Practices for Email Deliverability

Best Practices for Email Deliverability

Aeon/Amphibic has already configured and tested the technical authentication (SPF, DKIM, and DMARC) for your domain. While no single method can 100% guarantee an email will never be flagged as spam, combining this technical foundation with the following behavioral habits provides the best possible strategy to avoid your legitimate emails being routed to spam folders:

1. Use Meaningful Subject Lines & Message Bodies Avoid leaving the subject line or message body blank. Automated filters view “silent” emails—especially those containing only an attachment or a single image—as high-risk. Including a sentence or two of context helps filters recognize the email as legitimate communication.

2. Manage Your Recipient Count Adding a large number of recipients in the To, CC, or BCC fields (generally more than 10–15) can negatively impact your deliverability score. For larger groups, it is safer to send separate emails or use a dedicated mailing service.

3. Avoid “Spam-Like” Formatting Certain visual triggers often cause filters to take a closer look at your message:

• Avoid ALL CAPS: Using capitalized subject lines is a classic spam trait.

• Limit Punctuation: Do not use excessive exclamation points (!!!) or question marks.

• Be Selective with Words: Avoid “trigger” words like “Free,” “Winner,” or “Urgent” in the subject line.

4. Be Mindful of Links and Images

• Avoid Link Shorteners: Services like Bitly or TinyURL are frequently used to hide malicious destinations; filters may flag them on sight. Use the full URL or hyperlink your text directly.

• Maintain an Image-to-Text Ratio: Avoid sending emails that consist only of a single large image (like a digital flyer). Ensure there is plenty of typed text so filters can “read” the message.

5. Professional Grammar and Reputation Consistent spelling and grammatical errors are hallmarks of phishing attempts. Maintaining professional writing standards helps protect your domain’s long-term reputation with major providers like Gmail and Outlook.

6. The “Safe Senders” List The most effective way to improve delivery is to ask your regular contacts to add your email address to their Contacts or Safe Senders list. This creates a direct “trust” signal between your mail server and theirs.

7. Marking “Not Spam” If a recipient finds your email in their spam or junk folder, ask them to manually mark the message as “Not Spam” or “Move to Inbox.” This action “trains” the recipient’s email provider to recognize your address as a trusted sender.

For Our Business Clients

To further professionalize your communication and satisfy modern security filters:

• Include a Standard Email Signature: A professional signature provides “social proof.” Ensure yours includes your Company Name, Physical Address, and Telephone Number.

• Use Descriptive Hyperlinks: Instead of using “Click Here,” use descriptive text like “View the Project Proposal” or “Visit our Website.”

Managing Your Domain Reputation

Your “Domain Reputation” is like a credit score for your email. It isn’t just about the age of your domain, but how people interact with your mail. Whether you have a brand-new domain in its first 60 days or an existing domain that is currently struggling with spam folders, the strategy for building or “healing” your reputation is the same:

• Start with Quality, Not Quantity: Focus on sending high-quality, individual emails to known contacts rather than large blasts. This establishes a history of “wanted” mail.

• Encourage Engagement: A two-way conversation is the strongest signal to a mail filter that you are a legitimate human sender. A simple way to do this is to add a line such as “Please let me know if you have received this” or “Please acknowledge receipt” to your outgoing messages.

• The Power of the “Not Spam” Click: If a message is filtered, asking a client to move it to their inbox is the fastest way to “reset” the filter’s opinion of your domain.

• Avoid Sudden Volume Spikes: Do not suddenly send a massive newsletter to a large list if you haven’t been active. This can lead to a “reputation hit” that is difficult to reverse.

• Proactive Testing (Pro-Tip): You can jumpstart your reputation by sending test emails to your own personal accounts (Gmail, Outlook, etc.) or to friends and family. Ask them to:

  1. Check if the mail arrived in the Inbox or Spam folder.

  2. If it is in Spam, mark it as “Not Spam” and move it to the Inbox.

  3. Reply to the email immediately. These actions provide the fastest “trust” signals to global mail providers.