Avoiding the spam folder: Best practices for email deliverability

You’ve written a great email. Your list is ready. You hit send, and then...crickets.

It’s not always about your content. Sometimes your emails aren’t reaching inboxes at all; they’re landing in the spam folder.

Improving your email deliverability means ensuring your messages are actually making it into your subscribers' inboxes. That’s where the real engagement starts.

In this post, we’ll walk you through email deliverability best practices, including some technical essentials, to help your emails avoid spam traps and reach the right audience.

What Is Email Deliverability?

Email deliverability is the ability of your emails to reach your subscribers' inboxes, not their spam folders. Even if your email system shows a 100% delivery rate, that only means the email was accepted by the recipient's server. It doesn’t guarantee that it landed in the inbox.

Best Practices to Improve Email Deliverability

1. Authenticate Your Emails

To prove you’re a legitimate sender and not a spammer, set up key authentication protocols:

• SPF (Sender Policy Framework): Confirms your server has permission to send email on behalf of your domain.
• DKIM (DomainKeys Identified Mail): Adds a digital signature to your emails, verifying they haven’t been tampered with.
• DMARC (Domain-based Message Authentication, Reporting & Conformance): Builds on SPF and DKIM to protect your domain from spoofing and phishing.

Setting these up correctly is critical, and most reputable email platforms offer tools or guides to help.

2. Warm Up Your IP Address

If you’re sending emails from a new domain or dedicated IP, you need to gradually increase your sending volume over time. This is called IP warm-up.

Jumping into high-volume sending too quickly can flag your IP as suspicious, damaging your sender reputation. Instead, start by sending to your most engaged subscribers and scale up slowly.

3. Maintain a Healthy Email List

Quality always beats quantity. Keep your list clean by:

• Regularly removing inactive or bounced email addresses
• Avoiding purchased or scraped email lists
• Using double opt-in to confirm subscribers genuinely want your emails

Engagement (opens, clicks) tells inbox providers your emails are wanted — which boosts deliverability.

3. Maintain a Healthy Email List

Quality always beats quantity. Keep your list clean by:

• Regularly removing inactive or bounced email addresses
• Avoiding purchased or scraped email lists
• Using double opt-in to confirm subscribers genuinely want your emails

Engagement (opens, clicks) tells inbox providers your emails are wanted, which boosts deliverability.

4. Avoid Spammy Content and Triggers

Spam filters scan your subject lines and content for red flags. Best practices include:

• Avoiding excessive capital letters, exclamation marks, and hype words
• Keeping your text-to-image ratio balanced (too many images can look suspicious)
• Including a clear unsubscribe link (both required by law, and good practice)

5. Send Consistently and Monitor Performance

Sudden spikes in volume, irregular sending, or large attachments can all harm your sender reputation. Instead:

• Stick to a consistent schedule
• Monitor your open and bounce rates
• Segment your audience for more relevant, personalised content

6. Use a Reputable Email Service Provider (ESP)

Platforms like Mailchimp, Iterable, Klaviyo, and others help manage deliverability by offering shared IPs with good reputations, built-in authentication tools, and bounce handling.

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In summary, email deliverability isn’t just a technical detail, it’s the foundation of effective email marketing. If your emails aren’t being seen, they can’t be opened, clicked, or converted. By combining authentication, proper list management, and smart sending practices, you can significantly boost your chances of reaching the inbox.

Need help setting up your email infrastructure or warming up a new domain? Get in touch — we can get your campaigns running smoothly and safely from day one.

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