Brevo Deliverability: Why Emails Land in Spam and How to Fix It

Getting filtered into spam is every email marketer's nightmare. You put time into crafting the perfect campaign, hit send, and your open rate is suspiciously low. Spam filtering is sophisticated, but the reasons emails get caught are predictable — and preventable.

The Most Common Reasons Emails Go to Spam

1. Missing or Failed Email Authentication

If your domain lacks proper SPF, DKIM, and DMARC records, receiving mail servers can't verify that Brevo is authorised to send on your behalf. Many servers will route unauthenticated emails directly to spam or reject them entirely.

Brevo fix: Set up domain authentication in Settings → Senders, Domains & Dedicated IPs → Domains. Our dedicated SPF and DKIM guide covers this step by step.

2. Low Sender Reputation

Your sender reputation is a score that receiving mail servers assign to your sending domain and IP address. It's based on engagement data (open rates, click rates), bounce rates, spam complaint rates, and sending consistency.

A low reputation is the root cause of most deliverability problems.

Brevo fix: Brevo monitors your sender reputation and alerts you to issues. Improve reputation by sending consistently, keeping your list clean, and only emailing engaged subscribers.

3. High Bounce Rate

A bounce occurs when an email can't be delivered. Hard bounces (permanent failures — address doesn't exist) are particularly damaging. Continuing to send to addresses that hard-bounce signals to ISPs that you're not maintaining your list.

Brevo automatically suppresses hard-bounced addresses. But if you imported an old or purchased list, you may be starting with a high number of invalid addresses.

Brevo fix: Before importing any list, validate it with an email validation service. After import, monitor your bounce rate in campaign statistics and remove problematic addresses.

4. High Spam Complaint Rate

When recipients click "Mark as Spam" in Gmail or Outlook, this is registered as a spam complaint. Even a complaint rate of 0.5% can damage your sender reputation significantly.

Common causes:

• Subscribers forgot they signed up
• Email frequency is too high
• Content feels irrelevant
• Unsubscribe process is too difficult

Brevo fix: Use double opt-in for new subscribers, email at a consistent and reasonable frequency, and make the unsubscribe link prominent and easy to use.

5. Spam Trigger Words in Subject Lines

Certain phrases reliably trigger spam filters — "Free money," "Act now," "Guaranteed," "You've been selected," excessive punctuation, and ALL CAPS segments.

Brevo fix: Write subject lines that accurately describe the email's content. Avoid hyperbole, urgency manipulation, and free offer language.

6. Broken HTML or Excessive Images

Emails that are 95% images (with minimal text), have broken HTML, or contain suspicious scripts will often be caught by spam filters. Spam filters can't read text inside images, so image-heavy emails look like they're hiding something.

Brevo fix: Aim for a 60% text / 40% image ratio. Brevo's editor handles HTML cleanly. Always include alt text on images.

7. Sending to Inactive Subscribers

Continuing to send campaigns to contacts who haven't opened an email in 6+ months tells ISPs that your content isn't wanted. This depresses your engagement metrics and gradually hurts your sender score.

Brevo fix: Segment your list and run a re-engagement campaign for inactive subscribers. Those who still don't engage after a re-engagement sequence should be removed from your active list.

8. No Physical Address in Email Footer

CAN-SPAM (US) and CASL (Canada) regulations require a physical mailing address in every marketing email. Missing this is a red flag for spam filters.

Brevo fix: Add your physical address to your email footer. Brevo's templates include a footer section — fill it in and save it as a default.

How to Check If You're Landing in Spam

Use a tool like Mail-Tester (mail-tester.com) to send a test email and get a spam score. Aim for a score of 9/10 or higher.

In Brevo, monitor your campaign statistics for open rates. An open rate below 15% often indicates deliverability problems worth investigating.

Building a Strong Sender Reputation with Brevo

Brevo's infrastructure gives you a strong starting point, but reputation is ultimately earned through consistent, quality sending:

• Only send to people who explicitly opted in
• Send at a consistent frequency (not sporadic blasts)
• Make your content genuinely valuable
• Keep your list clean by removing non-openers periodically
• Monitor and respond to deliverability alerts in Brevo

Brevo Pricing at a Glance

All plans include unlimited contact storage. See full pricing on Brevo →