fuze32 Marketing Blog

Avoiding the Spam Folder: Best Practices for Email Deliverability

Written by Carrie Berkbuegler | Aug 29, 2025 1:00:00 PM

You've crafted the perfect email. The kind with a clever subject line, a gorgeous layout, and an irresistible offer that might as well have "click me" stamped all over it. You hit send and then… nothing. No opens. No clicks. No sales. Where did this email masterpiece go? Straight to the spam folder, the digital Bermuda triangle.

Don't worry, though. You're not alone. Email deliverability is the unsung hero (or villain) of email marketing. Think of it as the bouncer to your brand's email nightclub. If you don’t play by the rules, your emails won’t even get through the front door.

Lucky for you, I've got the scoop on how to keep your campaigns out of the dreaded spam folder and ensure they're actually seen. Let's talk about what email deliverability really looks like, why it matters, and how you can master it.

Key Takeaways: 

  • Build and Protect Your Sender Reputation: Keep spam complaints low, send to clean and active lists, and authenticate your emails with SPF, DKIM, and DMARC.
  • Craft Inbox-Friendly Content: Avoid spammy language, balance text and images, and personalize emails to resonate with your audience.
  • Clean and Segment Your Email List: Regularly remove inactive subscribers, use double opt-ins, and tailor content to specific audience segments.
  • Boost Engagement: Encourage opens, clicks, and replies with interactive content, A/B testing, and relevant offers.

The Reality of Email Deliverability

First, some cold, hard truths you need to know:

  • Around 20% of legitimate marketing emails never even make it to the inbox. Yikes.
  • Nearly 45% of global email traffic is spam—that's why those filters are working overtime.
  • Subject lines matter. A lot. 69% of email recipients decide whether to open or report an email as spam based solely on the subject line.
  • For every $1 spent on email marketing, there’s an average return of $42—but only if your emails actually land in the inbox.

Translation? If you're not taking your email deliverability seriously, you’re leaving massive potential (and money) on the table.

Why Your Emails Keep Getting Ghosted

Email providers have stepped up their game, so it’s not just about who you send to or what you say. Here’s why emails often vanish into the void:

1. Your Sender Reputation Is Dragging You Down

Think of your sender reputation like your email credit score. If it’s bad, email providers will treat you like that spammy cousin who only calls when they need something.

A healthy sender reputation depends on:

  • Keeping your spam complaints low
  • Sending to clean, active recipient lists
  • Consistency in sending volumes
  • Not landing yourself on any email blacklists

Pro tip: Keep an eye on your reputation using tools like Google Postmaster Tools or SenderScore. If spam complaints are creeping above 0.1%, it’s time to revisit your strategy.

2.  Your Content Is Screaming "I’m Spam!"

ALL CAPS, excessive exclamation points!!!, and subject lines promising “FREE MONEY” signal danger to spam filters. Think of it this way—the louder and cheesier your content, the more likely it is to get dumped into the junk pile.

Also, don’t overload your email with images and skimp on text. Filters love balance, and emails with too many images and not enough text scream, “Look at me, I’m shady!”

3. Your Technical Setup Is a Hot Mess

This is where things get a bit techy, but don’t run away just yet. If your emails aren’t authenticated properly, inbox providers won’t trust you. Think of it like showing up at an exclusive event with no ID. No ID? No entry.

Make sure your emails have:

  • SPF (Sender Policy Framework)
  • DKIM (DomainKeys Identified Mail)
  • DMARC (Domain-based Message Authentication, Reporting and Conformance)

Setting these up authenticates your emails and proves you're not some phishing scam from a random server in the middle of nowhere.

4. Your Audience Feels Ignored

Is your idea of marketing sending the same email to your entire list without a hint of personalization? That’s why half your audience is tuning you out. People want to feel like individuals, not just another name on a mailing list. Nobody has time for generic emails.

Lists that aren’t segmented for relevance often see significantly lower open and click rates than those that are.

How to Increase Email Deliverability Like a Pro

Alright, enough about what NOT to do. Here’s how you level up.

1. Clean Your Email List… Religiously

A messy list is like leaving expired milk in the back of the fridge. Clean it up! Here's how:

  • Remove inactive subscribers (if they haven’t engaged in six months, it’s time to say goodbye).
  • Implement double opt-ins for new subscribers.
  • Use email verification tools to catch fake or mistyped addresses.

This process not only improves your deliverability but also increases open rates. Less is more when it comes to your subscriber list.

2.  Start Small With New IPs

If you're using a new IP address, it’s vital to warm it up. Don’t go from 0 to 10,000 emails overnight. Instead:

  • Start with small volumes.
  • Send to your most engaged subscribers first.
  • Slowly increase your sending over a few weeks to build trust with inbox providers.

3. Authenticate, Authenticate, Authenticate

SPF, DKIM, and DMARC aren’t just buzzwords; they’re necessities. Setting these up tells providers you’re legitimate and keeps your emails from being flagged.

4. Craft Inbox-Worthy Email Content

Yes, reputation matters more than content these days, but don’t slack off here either:

  • Avoid spammy keywords like “free,” “guaranteed,” and “limited time.”
  • Stop yELLINGgg (a.k.a., no all caps).
  • Keep a solid image-to-text ratio (around 60% text and 40% images is a good rule of thumb).
  • Use tools like Mail Tester or GlockApps to check your emails before hitting send.

5. Personalize and Segment

Want fewer emails marked as spam? Treat your audience like humans. Segment your list by:

  • Engagement level
  • Interests
  • Purchase history

Then, send them content they actually care about. A little personalization goes a long way in the inbox.

6. Boost Engagement

Engagement isn’t just nice to have; it’s critical for email deliverability. Get your subscribers to open, click, reply, and share your emails.

Here’s how:

  • Ask questions or include surveys.
  • Try quizzes or interactive elements in your emails.
  • Use A/B testing to discover what resonates with your audience.

Moving Forward With Deliverability Mastery

Email deliverability might not be the most glamorous part of marketing, but it’s arguably one of the most important. After all, what’s the point of the perfect email campaign if it ends up being invisible?

By cleaning your list, building a strong sender reputation, and creating content that connects, you’ll go from being spam-foldered to inbox-preferred in no time.

Remember, email isn’t just a tool for sales. It’s a way to connect directly with your audience. Treat those inboxes with care, and they’ll treat your business with clicks and loyalty.

Now, go forth and conquer the spam filter. Your emails deserve to be seen!

Top 5 FAQs: Avoiding the Spam Folder

1. What is email deliverability, and why is it important?

Email deliverability ensures your emails land in recipients' inboxes instead of spam folders. Without it, even the best email campaigns won’t drive results.

2. How can I check and improve my sender reputation?

Monitor your sender reputation using tools like Google Postmaster Tools or SenderScore. To improve it, keep spam complaints low, send to clean lists, and avoid blacklists.

3. What are SPF, DKIM, and DMARC, and how do they help?

These are email authentication protocols that verify your emails are legitimate and protect your domain from being flagged as spam. Setting them up is essential for trust with email providers.

4. How often should I clean my email list?

Clean your list every 6 months by removing inactive subscribers, verifying email addresses, and using double opt-ins for new signups.

5. What are the best ways to avoid spam filters? 

Avoid spammy language (e.g., “free,” “guaranteed”), balance text and images, personalize emails, and segment your audience for relevant content.