You’ve written a great email. You’ve spent hours crafting your message, designing the layout, and setting the timing perfectly. But there’s one big problem — your audience never sees it.

Why? Because your email didn’t land in the inbox.

At EmailSchool, we teach that email deliverability is the invisible foundation of email marketing success. Even the best content fails if it ends up in spam.

This article explains — in plain English — how email deliverability works, why it matters, and how tools like Brevo, Mailchimp, and ActiveCampaign help improve it.

1. What Is Email Deliverability (and Why It Matters)

Deliverability is not the same as “delivery.” Delivery means your email reached a server. Deliverability means it actually made it into the recipient’s inbox — not the spam or promotions tab.

Think of it like mailing a letter: It’s one thing if the letter arrives at the post office; it’s another if it’s actually handed to the right person.

A high deliverability rate (above 95%) means your sender reputation is strong.

According to Brevo’s 2025 report: “Brands with authenticated domains and consistent engagement average 97.8% inbox placement.”

2. The Invisible Enemies of Deliverability

Before you can fix issues, you must know what’s hurting you.

Common causes of poor deliverability:

• Spam-trigger words (e.g., “guaranteed money”, “100% free”)
• Using free email addresses (like Gmail/Yahoo) as sender
• Missing authentication (SPF, DKIM, DMARC)
• Buying or renting email lists
• Low engagement (people ignoring your emails)

At EmailSchool, we always say: “The inbox rewards relevance — not reach.”

3. The Three Pillars of Deliverability

To land in inboxes, focus on three foundations:

a. Authentication

This proves you’re a legitimate sender. The “ID card” of your domain includes:

• SPF (Sender Policy Framework) — defines which servers can send emails for you.
• DKIM (DomainKeys Identified Mail) — adds a digital signature to verify authenticity.
• DMARC — prevents impersonation and phishing.

Platforms like Brevo and Mailchimp automatically guide you through these steps when setting up your domain.

b. Reputation

Your reputation is built by how subscribers interact with your emails.

If users open, click, and reply → good reputation. If they ignore or mark as spam → bad reputation.

Pro Tip from EmailSchool: Start with small sends. Don’t blast thousands of emails on day one — that looks suspicious to email providers.

c. Engagement

Gmail, Outlook, and Yahoo use machine learning to track engagement.

If people open your emails, save them, or reply or forward them...your domain gains “positive points.”

Brevo’s “Smart Send” feature adjusts send times based on engagement data, helping improve inbox placement.

4. Why Domain Authentication Is Non-Negotiable

Many small businesses skip domain setup because it looks technical. But without it, your emails look fake. Gmail, Outlook, and Yahoo are now enforcing stricter authentication policies (as of 2025).

Quick Checklist:

• Have you added SPF records in DNS?
• Have you configured DKIM?
• Do you have a DMARC policy (even “p=none”)?

Brevo offers a simple DNS setup wizard — and Mailchimp provides prefilled TXT record instructions.

5. Content Quality Affects Deliverability

Spam filters analyze your content before inboxing it.

Avoid:

• Overusing capital letters
• Too many exclamation marks!!!
• Hidden links or attachments
• Spammy phrases like “risk-free”, “click here now”, or “act fast”

EmailSchool Tip: Write naturally — like you’re talking to a friend, not selling to a stranger. Focus on value and education, not sales pressure.

6. Send Frequency and Consistency

Sending too often = looks like spam. Sending too rarely = looks inactive.

The sweet spot? Weekly or biweekly emails, consistently.

Brevo’s automation tools let you schedule educational sequences without overwhelming users. At EmailSchool, we recommend “value rhythm”: send only when you have something genuinely helpful.

7. Clean Your List Regularly

Inactive subscribers hurt your sender score. Once a month:

• Remove bounced addresses
• Remove emails that haven’t opened in 90 days
• Segment your list by engagement level

Tools like ActiveCampaign and Brevo allow automatic list cleaning and re-engagement campaigns.

Remember: A smaller, active list beats a large, silent one.

8. Optimize the “From” Field and Reply-To

Always use your brand domain: news@emailschool.online instead of emailschool@gmail.com

And never use “no-reply” — it discourages engagement. Encourage replies! It signals to inbox providers that people value your emails.

9. The Role of Warm-Up Campaigns

If your domain is new, you must warm it up gradually. Send to small, engaged audiences first, then slowly increase volume over 2–4 weeks.

Tools like Brevo handle warm-up automation automatically — delivering in smaller batches to build reputation safely.

10. Measure What Matters

Don’t obsess over open rate alone. Focus on:

• Inbox rate
• Click rate
• Spam complaint rate
• Hard bounces

These tell you whether your sender health is improving.

Example: If open rate drops but spam complaints rise — you’re likely sending too often or using the wrong audience segment.

11. Use Double Opt-In

When users confirm their subscription, you ensure real engagement and avoid fake emails. Double opt-in improves:

• List quality
• Engagement
• Compliance (GDPR, CAN-SPAM)

Brevo and Mailchimp both make double opt-in setup one-click simple.

12. Segment by Engagement

Segmenting your list by behavior keeps deliverability strong. Example:

• Active subscribers: send weekly
• Inactive users: send re-engagement campaigns
• New signups: send welcome sequences

At EmailSchool, segmentation is rule #1 for staying out of spam.

13. Test Before Every Campaign

Before you hit “Send”, check:

• Inbox placement (using test accounts)
• Link tracking
• Load speed

Brevo’s pre-send test tool flags common spam triggers. Even small changes — like trimming one image — can improve inbox placement.

14. Maintain a Consistent IP and Domain

Switching domains or IPs frequently resets your sender reputation. Stick to one authenticated domain for all campaigns.

ActiveCampaign offers “Dedicated IPs” for stable sender reputation — useful for brands with 50,000+ monthly sends.

15. The Education-Based Deliverability Strategy

Finally, remember: Deliverability improves naturally when people love your content.

At EmailSchool, we call this the “Engagement Loop”: Value → Open → Click → Reply → Trust → Inbox

If your readers learn, click, and engage — Gmail will want to put you in the inbox.

Conclusion

Email deliverability isn’t about technical tricks — it’s about trust. Email providers reward consistent, authentic, and educational senders.

Whether you’re using Brevo, Mailchimp, or ActiveCampaign, focus on:

• Authentication
• Engagement
• Clean content

And always remember the EmailSchool principle: “Your email’s first job isn’t to sell — it’s to arrive.”