How to Avoid Spam Filters [30 Proven Tips]

April 16, 2022

An email marketing campaign becomes successful when emails reach the recipients' inboxes. But, the subscribers never like to open spam filter marked emails. Thus, you should send a well-structured email to your subscribers to avoid spam filters.

According to research by ReturnPath, only 79% of emails from the genuine sender reach subscribers' inboxes (source: If you want to know How to Avoid Spam Filters, stay with us for a while.

Photographer: Visual Generation Inc.

What is a Spam Email Filter?

A spam email filter is an implementation of technology by ISP companies. This technology includes artificial intelligence to protect unusual, untrusted, and virus-infected emails. When artificial intelligence thinks any emails are untrusted, it marks them as spam automatically.

The spam filter does not affect the email deliverability rate. But, they down the possibilities of opening rate for the email marketers. To know how to avoid spam filters, you need to improve your email structure. Besides, you need to follow a few basic things; we will discuss in this article.

And if you don't want to land to your audiences spam box, it is better to switch to smart tools like Warmbase. Sign up right away to test it.

How to Avoid Spam Filters

You can easily avoid spam filters if you follow the below things.

1. Choose Reliable Service Provider

IP reputation is one of the key factors to avoid spam email filters. Yahoo, Gmail, and Zoho mail are reputed IP companies. You can use their domains to get successful emailing.


2. Use Double Opt-in Form

The subscribers do not report taking extra steps to get a subscription. So, provide a double opt-in form by sending an email to subscribe.

3. Avoid Trigger Words

Using trigger words in the subject line or email body may be the reason for the spam marks. 54% percent of recipients mark spam when they receive trigger words in the subject line (source:

4. Ask to Add You in Contact List

When you send an email to your subscriber, ask them to add you to their contact list. If they add your email address to their contact list, your email will pass the spam filter.

5. Send High-end Content

Suppose, you have got a subscriber who gets your emails inboxes directly. But they do not open to read your emails regularly. In that case, your spam count will increase. So, try to send high-quality content. And attract the subscriber to read your email regularly. More strategies you can learn from How to Avoid Spam Filters.

6. Use Recognizable Sender Name

The sender's recognizable name should be added to the email. An email name that matches the sender's name enhances the authenticity. So, use the sender's name, designation, and contact number at the end of the email.

7. Get Certified by Third Party

This is another way to establish the authenticity of the email addresses. After getting certified, your email spam rate will decrease. Then you can send emails directly to the recipients' inboxes. You can get both paid and unpaid services from third-party tools.

8. Check Your IP Address Reputation

If your email IP address is blacklisted, you can not reach the recipient's inbox. In that case, you can use tools like Multirbl. Valli or MxToolbox to check your IP address.

9. Avoid Unnecessary Attachments

Try to avoid documents, coupons, etc in your email. If your attachment takes a long time to download, the email may bounce or spam automatically.

10. Follow Regional Laws

Most countries have anti-spam laws to protect their data from spammers. If your country has anti-spam laws, follow them. Besides, maintain the other country's rules regarding email sending.

11. Avoid Heavy Images on Attachment

Spam filters block image files that contain heavy megabytes. Additionally, the filters block automatically when they find too many image files. So, you should attach 2 to 3 image files under 1-megabyte size each in an email.

12. Maintain Proper Ratio of Text and Images

Sending only images in cold email reduces the opening amount. Thus, you should include text and images with a balanced ratio. Mailchimp suggests maintaining 80% text and 20% image in a business email.

13. Remove Inactive Accounts

Many email users change their addresses frequently. As per a study by, 31% of people change their email after using a year. So, you should remove the inactive email accounts from your list to enhance spam-free emails.

14. Remove Inactive Subscribers

All the subscribers do not get interested in your content. Even, many of them lose their interest in your content too. In that case, you should observe their response rate for 3 to 4 months. If the accounts are found inactive, you should remove them too.

15. Use Email Tester or Content Checker

If you are still not passing spam filters, you can get help from online tools. The tools are specialized to test your email content, check the subject line, and so on. After going through your emails, the tools will suggest changes.

16. Never Purchase Email List

Purchasing an email list for a cold email campaign can not be a good deal. Even sending emails to an unknown person may damage your email reputation. Also, it increases the possibility of being stuck in a junk filter. So, you should not purchase an email list for a professional campaign.

17. Ask Twice for Subscription

If you already asked to subscribe to your emails, think for the second ask. If they do not subscribe yet, maybe they do after the second asking. In addition, if they already subscribed, your email engagement will increase.

18. Respect your Unsubscribers

Being unsubscribing means the person does not want to get notifications from you. In that case, you should respect their decision. And, I do not need to send emails again to them. Thus, you have to make their journey easy with the one-stop process.

19. Prepare a good Subject Line

Preparing a crafting subject line is an art in email marketing. With an attractive subject line, you can attract the recipients more. Another study says, 69% of recipients mark emails as spam based on the subject line (Source: So, you should focus on preparing a good subject line.

20. Never Write Shouting Lines

Using upper case words to write an email subject line seems rude. Though using upper case does not mark your email spam, it may alert spam filters. So, you need to avoid upper-case words in your email subject line.

21. Stop emailing people who have email bounced repeatedly

If you've been noticing that your emails to certain people are bouncing back more often than usual, it's a good idea to stop emailing them. Not only is it likely that they're not getting your messages, but each time an email bounces back, it raises your spam score. And once your spam score gets too high, your emails will start getting automatically filtered by spam filters. So if you're not getting through to someone by email, try another way of communication. Your message will probably get through a lot better - and you'll avoid getting caught in the spam filter trap.

22. Look after Your Email Body

Everything matters to establish a reputation through email to the subscribers. Preparing a good subject line is not the end. You need to focus on greetings, body, ending, and so on. You have to be well-mannered with the writing too. So, emphasis on preparing a good email body.

23. Avoid Ample Media on Attachment

High-resolution videos, GIF files, or flash animation files slow your email correspondence. Many IP service companies do not allow large-size files on attachments. Thus, you can share your website links or video links through your emails. By clicking the links, the subscribers will watch the videos or information.

24. Avoid Sending Too Many Hyperlinks

Too many hyperlinks in an email body may catch in the spam filter. So, you need to make a balance among, text, attachments, and links in an email body. However, you can use third-party tools for multiple hyperlinks management in your email.

25. Pay Attention to the Font Color and Size

The use of different sizes and color fonts in an email body can alert spam filters. Even, using varieties of fonts in an email reduces your impression of the recipients. From the Radicati group study, it has been found - that 60% of people do not accept irregular fonts. Besides, 70% of people prefer one size font in an email.

26. Revise Spelling and Grammar

Wrong spelling and grammatical errors are not acceptable in any professional email. An error can damage your credibility and image to the recipients. As a result, your email could become a reason for spam filter alerts. So, revise every email before sending it to the recipients. Correct all the spelling and grammatical errors to establish email reputation.

27. Leave an Unsubscribe Button

Keeping the unsubscribing button in an email is a great example of professionalism. So, prepare your email unsubscribing button and do respect the recipients' decision. And, keep limiting your email towards the subscribers.

28. Follow-up after Sending Emails

To develop relationships among the subscribers, you need to communicate with them regularly. In these circumstances, following up after sending an email is pretty effective. Besides, regular email following-up increases email engagement. That helps your email to avoid spam traps.

29. Do not Email to the Repeatedly Bounced People

If your email gets bounced repeatedly, you will not mail them again. Otherwise, you will be marked as a spammer by IP service providers. So, remove the email ID from your contact list that frequently bounced back.

30. Test your Email Before Sending

At present, you will find various types of devices to get emails. Mobile phones, desktops, laptops, and notepads, have varieties in their display. If your email sending tool has the previous options, you should check through them. Also, you should test your prepared email by sending it manually to pass spam filters.

Photographer: Visual Generation Inc.


Do Hyperlinks Get Caught In Spam?

If you send long hyperlinks, there is a possibility of getting caught in spam. To get free from spam, you can minimize your hyperlinks. So, you can create a clean hyperlink inside your email body. In this way, you can minimize the ratio of getting caught in spam with your hyperlinks.

What Email Has The Best Spam Filter?

There are various spam filters in the market. Some of them are free and some of them are paid tools. However, SpamTitan, Spambella, Xeams, and MailWasher are the best spam filters in the market.

How Many Hyperlinks Are Too Many For An Email?

Using too many hyperlinks in an email may be caught in spam filters. So, you need to attach a balanced number of hyperlinks between one-three in an email body. But not more than five.

Final Verdict

The ultimate goal of avoiding spam filters is to land in the recipients' inboxes without spam marking. Otherwise, your email campaign becomes useless. We hope, How to Avoid Spam Filters has already delivered all the solutions.

However, you should follow the above 30 tips and techniques to avoid spam filters. To advance your services, you can warm up your email. By getting a warm-up service from, you can increase your email deliverability too.

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A passionate Creative Strategist with 10+ years of experience in developing organic content strategies for financial sector businesses; skilled in animation, visualization, writing to build, manage, execute growing brand identity, and maximize productivity.
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