The Ultimate Guide to Email Deliverability

Stop Your Emails From Going to Spam

An essential guide to understanding email authentication and ensuring your messages reach the inbox.

Why does this happen?

Every day, billions of spam emails are sent. To protect users, email providers like Gmail and Outlook use a system of "trust signals" to verify if an email is legitimate. If your domain is missing these signals, your emails get flagged as suspicious.

~85%

of all emails sent are considered spam.

The 3 Pillars of Email Authentication

SPF, DKIM, and DMARC are DNS records that act as your domain's ID card. They prove to receiving mail servers that you are who you say you are.

1. SPF

Sender Policy Framework

What it is: A public list of all servers authorized to send email from your domain.

Why it matters: It prevents scammers from sending emails using your address (spoofing).

2. DKIM

DomainKeys Identified Mail

What it is: Adds a unique, encrypted digital signature to every email you send.

Why it matters: It proves the email content hasn't been tampered with and truly came from you.

3. DMARC

Domain-based Message Authentication

What it is: An instruction manual that tells servers what to do if an email fails SPF or DKIM checks (e.g., "send to spam" or "reject it").

Why it matters: It enforces your SPF and DKIM rules, protecting your brand's reputation.

The Impact of Proper Authentication

Without Authentication

Emails are often treated as suspicious, leading to poor deliverability.

With Authentication

Mail servers trust your emails, dramatically increasing inbox placement.

How a Mail Server Thinks

When an email arrives, the receiving server asks a series of questions based on your authentication records.

New Email Arrives

Check 1: Does SPF Pass?

(Is the sending server on the approved list?)

Check 2: Does DKIM Pass?

(Is the digital signature valid?)

Check 3: What's the DMARC Policy?

(What should I do if checks fail?)

Checks Pass?
→ INBOX
Checks Fail?
→ SPAM / REJECT

Other Common Issues

Factors Affecting Deliverability

  • 🌐

    Poor IP Reputation

    If the mail server's IP has been used for spam before, it hurts everyone using it.

  • ✍️

    Spammy Content

    Using too many links, certain keywords, or all-caps can trigger filters.

  • 🚫

    Domain Blacklists

    Your domain or IP might be on a public list of known spammers.

Relative Impact on Deliverability

Your 3-Step Action Plan

1

Contact Your Mail Provider

Ask them for the correct SPF, DKIM, and DMARC records for your domain. They must provide these to you.

2

Contact Your DNS Provider

Give them the records from your mail provider and ask them to add them to your domain's DNS settings.

3

Review Sending Practices

Avoid spammy subject lines and content. Send valuable emails that your recipients want to receive.

By taking these steps, you build trust with email providers and protect your professional reputation.

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