How To Avoid Email Going To Spam & Improve Deliverability

Why Even Good Emails Land in Spam

Avoiding spam is a challenge faced by marketers worldwide. The number of emails landing in spam folders rose to 8.6% in Q4 2024, according to Validity's Email Deliverability Report.

As one marketer shared on Reddit, even well-crafted campaigns can be identified as spam. "I work for a local reputable company with the email not having anything bad in it,” the post said.

Replies to this Reddit user emphasize the role of ESPs, and understanding how they operate is crucial in knowing how to stop your emails from going to spam. Every ESP has spam filters that run on sophisticated algorithms to determine which messages reach the inbox and which ones are directed to the junk mail folder.

Emails go to spam when one or more red flags—which we identify below—activate spam filters. When your email's spam score exceeds a specific threshold, the filter will mark it as spam.

Bad sender reputation

Each Internet protocol (IP) address—or the unique numerical label assigned to your device—has a history monitored by ESPs. If your IP address has had a high volume of spam complaints and a high bounce rate, the ESP may filter or block new messages as spam.

Poor list hygiene

Not taking the time to "clean" your contact list regularly by removing invalid or expired addresses can cause hard bounces or returned mail.

Spammy content

Spam filters have been trained to associate specific phrases (see the next section) with scams and email spoofing.

Spoofs mimic branding and content from well-known entities. Their seemingly legitimate—but questionable—requests may include any of the following:

• Resetting your password or updating/verifying your account or billing information.
• Contacting your service provider's tech support team for an issue you didn't report.
• Paying an outstanding invoice for a product or service you're unaware of.
• Contacting an organization for jobs or financial assistance.

Spam scoring systems differ from one mailbox provider to another. However, they all aim to protect email users from unsolicited and dangerous emails, including phishing attempts and malware attacks.

10 Proven Ways to Keep Emails Out of Spam

Knowing the causes is half the battle. Here’s how to fix emails going to spam:

1. Authenticate your emails

Gmail, Outlook, and Yahoo require email senders to follow security protocols. We discuss these three protocols—SPF, DKIM, and DMARC—in our guide on How to Improve Email Deliverability. A new security standard, Brand Indicators for Message Identification, allows email senders to display their brand logo to improve visual trust. Once in place, they enable ESPs to verify you as the true sender.

2. Update and verify your recipient list regularly

Fake and inactive addresses can lead to emails bouncing or going to spam. Your click-through and open rates can also decline as a result.

Verified Email is one of the best tools for email list scrubbing. Clean smaller lists every six months and large, frequent-send lists quarterly or monthly to ensure email deliverability.

3. Use double opt-in and preference centers

Industry best practice dictates using a double opt-in form when accepting subscribers. After they sign up, recipients receive an automated email to confirm their subscription. This step also reduces soft bounces, because truly interested individuals will verify their email addresses (particularly the spelling) before confirming.

You may also create a preference center or page, where subscribers can select the types of content they'd like to receive and how often.

4. Segment recipients of your email campaigns

Email segmentation means grouping subscribers based on common characteristics. You can classify them according to engagement level, purchase history, demographics, psychographics (interests), or website behaviors (pages visited, content downloaded, or cart abandonment).

5. Monitor sender reputation and avoid deny lists

Engagement (click-through and open rates), sending volume and frequency, bounce rates, spam complaints, and unsubscribe rates are among the metrics used to evaluate you as a sender. Track your sender reputation score using platforms such as Google Postmaster Tools, Microsoft SNDS, and Sender Score by Validity.

Doing so will keep you away from deny lists (also called blacklists or blocklists) of IP addresses and domains known for sending malicious or spam content. While ESPs keep internal lists, they also refer to those compiled by anti-spam organizations such as Spamhaus Block List and SpamCop Blocking List.

6. Avoid spam trigger words

When asked “how to avoid spam filters in email marketing,” don’t use these gimmicks so you can earn subscriber trust:

• Excessive punctuation or emojis
• All caps
• Pushy sales language or unrealistic promises: "Last Chance," "Get paid fast," or "No Hidden Cost"

Rephrase your promotional messages using less aggressive wording, starting with your subject lines.

Instead of: "ECOMMERCE SECRETS INSIDE"

➡️ Say: "5 Strategies to Double Your Revenue"

Instead of: "Limited time"

➡️ Say: "Available until [specific date]"

Instead of: "Important! Your account needs immediate attention!"

➡️ Say: "Your trial ends November 7 — Renewal options"

7. Limit images and large files

Compress large images to ensure emails are under 100 KB with a 60%-40% text-to-image ratio. Include a descriptive ALT text for accessibility, and in case images fail to load. Also, include an HTML and plain text version of your email. Share links to files instead of adding them as attachments.

8. Optimize sending frequency and warm up new domains

A/B test your sending times, then view your ESP's report on click and open times. You may also ask subscribers directly by providing an option on your preference center/page. Finding the ideal rhythm will prevent email fatigue.

Warm up an email domain by gradually raising the number of sent messages in two to four weeks, according to your performance metrics.

9. Boost engagement signals

Try these steps to encourage engagement, so ESPs will recognize your messages as legitimate and non-spam:

• Ask recipients to whitelist your address ("Please add us to your contacts") or send a message, requesting them to reply if they wish to continue receiving your messages.
• Consider sending more emails to your most engaged subscribers. Meanwhile, identify recipients who haven't engaged in six months and one year. Send fewer emails to each group in descending order—this is also known as sunsetting.
• Add an unsubscribe link to the top and bottom of your email.

10. Maintain a consistent "from" name

Choose a name—typically your company/product name or a specific department—that will be recognizable to subscribers. Conduct an A/B test for optimal impact. Use the same sender name across platforms and email campaigns. Moreover, avoid a “no-reply” address as it comes across as uncaring to subscribers.

A recent Airship survey shows that 33% of consumers mark emails for deletion "by scanning who it is from." Meanwhile, 77% of respondents to a Twilio SendGrid report said email senders "strongly or somewhat strongly influence" their decision to open an email.

Quick Checklist

Follow these 10 steps to stop emails from going to spam and improve inbox placement:

1. 1. Authenticate Your Emails (SPF, DKIM, DMARC, BIMI).
2. 2. Update and verify your recipient list regularly with tools such as Verified Email.

Check if your email is valid with VerifiedEmail
Verify
3. 3. Use double opt-in and preference centers.
4. 4. Segment and personalize email campaigns.
5. 5. Monitor sender reputation and avoid deny lists.
6. 6. Avoid spam trigger words and formatting issues.
7. 7. Limit images and large files.
8. 8. Optimize sending frequency and warm up new domains.
9. 9. Boost engagement signals.
10. 10. Maintain a consistent "from" name.

Keep Your Emails Out of Spam for Good

Emails going to spam is a dilemma you can prevent and fix by applying the 10 best practices discussed in this guide. To help keep your contact list clean and improve deliverability, consider including Verified Email in your workflow. With its list management automations, you only send to real and engaged subscribers, helping you improve your engagement and sender reputation.