Marketers spend days writing engagement emails, but one single mistake can sometimes collapse all the efforts. Whether you overuse spam words, send too many emails at once, or your email service provider (ESP) glitches, you may trigger email spam filters, a death sentence to your outreach campaign.
Email spam filters protect users from potential spam for a reason: nearly 49% of all global emails are spam. But the system is kind of blind, so it may block completely legit emails that, for some reason, look dubious or resemble spam emails.
Read on to learn how to avoid email spam filters so your reputation is preserved and all your emails are delivered to the destination point: the recipient’s inbox.
What Are Email Spam Filters?
Spam filters for email detect and identify potentially harmful emails and then send them to the spam folder. This way, ESPs ensure that users don’t receive unwanted letters in their inboxes.
There are three types of email traps:
- Pristine traps (honeypots): These are emails used by anti-spam organizations solely for monitoring and blocking purposes.
- Recycled traps: These are genuine emails that have been abandoned a long time ago and are now used by the ISP as a trap.
- Typo spam traps: These are actual addresses but with typos in the domain name, like @gmaiil.com, @yaoooh.com, etc.
Here’s how email spam filters analyze various email elements for spam:
| Subject Line | Spammers often use words designed to draw attention, such as “Money NOW!”, “Urgent message!”, or “Answer this ASAP”. If you implement this strategy in your subject lines, the system may mark the message as potentially harmful. |
| Email Body | Spam letters often have links to malicious websites or too many links per email. Don’t spam with links. Keep the message simple to avoid email spam filters. |
| Sender’s Email Address | Scammers often use non-legitimate email addresses. If your email looks like “[email protected]” or “[email protected],” spam filters may mark this address. |
| Sender’s IP address | If your IP address is compromised, the email spam filters may block you. |
| Sender’s Reputation | If you have a high bounce rate or many users mark your emails as spam, the ISP may suspect that you are sending harmful emails, so they block you. |
Overall, email spam filters react to a linkage between the sender and the readers’ actions. Most filters use a rule-based approach: once they find that the sender has disobeyed the rules, they mark this account as suspicious.
Simple email spam filters may block the account once they find spam-associated keywords. More sophisticated AI-based systems use pattern-recognition methods to analyze behavioral patterns in sender-user communication.
How Email Spam Filters Benefit The Industry
Email marketing spam filters reduce the amount of potentially malicious emails that can reach the mailbox, saving the user’s time because they don’t need to inspect and clean their mailings. As a result, users can safely open any letter in their mailbox.
Moreover, sophisticated gateway email spam filters can protect users from phishing attacks by proactively blocking suspicious senders.
Most Common Features of Spam Email Filters
If you are curious about how to get around email spam filters, you should know their features in the first place:
| Keyword Filtering | Modern spam filters check for common spam phrases and synonyms, so you should use paraphrasing techniques. |
| Heuristic filtering | Email spam filters use heuristic rules to identify potential spam emails. These rules are based on common characteristics of spam emails. Some spam filters are set up manually, while others are automatic. |
| Black lists | ESPs maintain a block of known spammers and phishing sites and share these lists with each other. |
| Greylisting | Some spam filters delay message delivery to prevent spammers from sending large volumes of emails before they gain a reputation as law-abiding. |
| Content filtering | Email spam filters identify phishing links and malicious attachments. Among fraudulent emails, 73% are phishing letters. |
| Machine learning | AI-based tools constantly train on datasets to discover hidden patterns of spam and phishing letters to train spam email filters. |
To keep a good sender score, look for the best way to set up email filters for spam prevention. Ensure that you deliver messages to all users in the list.
Beware that there is no single email provider with the best spam filters for every case: each business situation is different. Do your research to find out the best strategy and provider for you. It’s the only way to do email marketing while avoiding spam filters.
How To Get Past Spam Filters: 11 Proven Tips
Most spam email filters use similar guidelines, so you can use the same approach to improve your sender’s reputation. However, there are no publicly available datasets to test spam email filters, so you can only figure out the campaign’s effectiveness by measuring the changes in your open rates, click-through rates, and other crucial KPIs.
1. Send Newsletters From Your Domain
The most effortless way to protect your emails from being filtered is to use a custom mail server domain. That way, users can be sure that those letters are genuine and that spam filters won’t block them as a suspicious sender.
A custom domain name makes your business look more professional. It becomes your brand identity and allows you to control your online presence. Once you decide to change the mailing service provider, you can use a custom domain.
Source: Target
As you see, Target sends emails from its domain. Users can be confident they are receiving messages from Target, not from impersonators.
2. Authenticate Your Domain
Domain authentication is verifying that the domain owner assigns DNS records to the domain’s DNS zone, a crucial process that shows your validity as the sender. Then, the system sees you as a legitimate sender who cares about your reputation.
Authentication protects the domain from being used for phishing or other suspicious activities. Globally, 95% of all phishing attacks are done by email.
Domain authentication reduces the risk of brand damage and increases security by protecting the business from spoofing attacks. And you are less likely to get blocked by email marketing software spam filters.
There are two main ways to authenticate a domain:
- Use a third-party service such as Google Domains or Cloudflare
- Do manual DNS-based authentication via DKIM (DomainKeys Identified Mail) and SPF (Sender Policy Framework)
Once you authenticate the domain, you are capable of sending emails while avoiding spam filters.
3. Maintain a Strong Sender Reputation
A sender’s reputation is a measurement of their trustworthiness.
Here are some things that affect email spam filters:
- Domain authentication: Validated emails are more trustworthy. It positively affects the sender’s reputation, so providers mark you as a genuine user.
- Bounce rate: The overall percentage of bounced emails should not exceed 10-15%. Otherwise, email spam filters may identify you as a potential spammer.
- Compliance rate: The overall percentage of spam emails should not exceed 0.1%. Once you exceed this rate, spam email filters may flag your messages.
- Open rate: The percentage of open emails should vary between 15-30%, so spam filters for email won’t bother you.
- Click-through rate: The desired CTR for brand mailings should range from 2-5% by industry.
These are crucial factors in determining a sender’s reputation. The closer you are to the desired benchmarks, the better your reputation.
4. Maintain Your IP Reputation
There can be multiple senders under a single IP. If one of them damages the IP’s trustworthiness, it will affect each sender under the same IP. Spam email filters will block everyone under the same IP.
It can become a problem when law-abiding senders share their IP addresses with other, more reckless senders. If you are looking at how to avoid spam filters in email marketing, use a dedicated IP address so the behavior of other senders won’t affect you. Big corporations can use multiple dedicated IPs per brand, so email spam filters won’t disrupt their communication strategy.
Once you get a dedicated IP, check email content for spam filters at least once a week. Make sure that the chosen tool provides valuable insights about your CTR, open rate, etc. That way, you can track your reputation, so spam filters for email don’t mark your messages as potentially malicious.
5. Optimize Your Newsletter Copy
Traditional email spam filters can’t analyze email copy in detail, so they flag any content that has characteristics associated with spam. AI-based tools are more sophisticated, but still, you’ll be safe if you stick to the following rules to get around email spam filters:
- Personalize the message to ensure it fits the user’s needs. Use responsive templates for this task.
- Don’t use too many exclamation points. It looks unprofessional. Some users may flag your message, and spam email filters react by blocking you.
- Spell-check the letter. Typos may set your reputation as an irresponsible business.
- Use high-quality images and videos. If you need to fit a long video into the letter, upload it to YouTube and embed it into the message. If files are too big or in a weird format, email marketing software spam filters react to it as if it were a malicious file.
- A/B test various approaches to find out which works best for different audiences.
- Use a consistent tone of voice throughout the whole communication.
- Write a catchy CTA. Tell the subscribers what you want them to do. Your calls to action should be concise, clear, and persuasive.
Grammarly mailings consistently demonstrate email personalization. Each week, the team sends emails to users, reflecting on their progress. Once a user reaches certain milestones, the company shares the new achievements with them.
Source: Grammarly
6. Avoid Spam Trigger Words
There are no magic phrases to improve open rates or get along with email spam filters. However, trigger words can cause more harm than good. Use them with caution or eliminate them from mailings for good.
Check the following tips about email subject lines to avoid spam filters:
- You don’t need to sound desperate. It pushes people away from you. Don’t use phrases like “Please read!”, “Pinky Promise.” Spam filters for email blacklist senders who use desperate words.
- You don’t want to sound pushy with words like “act NOW!”, “No catch,” or “You can’t live without it.” Those words push people away, so spam email filters mark them as trigger phrases.
- Don’t try to sound outlandish like Saul Goodman from the eponymous series. Avoid phrases like “Totally free,” “No risk,” “Win big money,” “Ultimate cash bonus,” etc. Play it safe so spam filters for email don’t mark your messages as potentially harmful.
The only exception to this rule is if you have a fun, ironic tone of voice and the email is a satire. However, even in this case, you don’t need to use multiple trigger words in one letter to avoid spam filters in email marketing.
If you are unsure that the chosen phrase is a trigger, use other words with a similar context. Don’t let spam email filters block you due to wrongly used words.
7. Optimize Your Image-to-Text Ratio
If the pictures in your message are too large or are in a complex file type, they may appear malicious to email spam filters. Optimized images can make your emails more appealing and persuasive, improving CTR.
Resize the image to fit the chosen email template to avoid email spam filters. Compress it to reduce file size and use a web-friendly image page format like JPG, JPEG, GIF, or PNG.
Don’t use larger and slower formats like TIFF or RAW – if the image loads slowly, most users close the website. Instead, use responsive templates that change the image resolution, text color, and size to adapt to the device.
8. Check Your Link Quality
The quality of your links matters. If you constantly link to suspicious external sites, email spam filters notice it and flag you. Therefore, use link checker tools to identify potentially low-quality links and remove them from your link-building strategy.
9. Test Your Emails Before Sending
Once your email is ready, test it with different email clients and providers before you launch the campaign. For example, emails with poor layouts look unprofessional, pushing users away, but you can still fix it at the final stage.
Besides, ask for feedback from your subscribers. Provide them with additional benefits for it, such as a discount or free delivery. That way, you’ll get to know how to send bulk email and bypass spam filters in your situation.
10. Don’t Use Purchased Lists
Purchased lists are email addresses collected from public records, which means many of them may not even be real. Send too many emails to the wrong addresses, and you’ll end up being blocked by your ESP.
Instead of buying emails, build your email list and examine it occasionally; even a genuine email list must be pruned occasionally. For example, you have to regularly check your email list for hard bounces and remove such addresses.
The first thing that you need to do in your email campaigns is to delete all addresses that face a hard bounce. Check out the list and remove typo traps to avoid spam filters. Write down soft-bounced addresses and check them a few weeks later.
11. Let Them Unsubscribe
It may seem counterintuitive, but allowing people to unsubscribe will boost your mailing quality, open rates, deliverability, and CTR, eventually growing your sender’s reputation and helping you prevent spam filtering.
Take Control of Your Email Marketing with MailCon
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Frequently Asked Questions
Why do emails go to spam instead of the inbox?
Emails usually go to spam because your ESP thinks you’re sending low-quality, spammy, malicious, or downright fraudulent emails. Such treatment usually happens if the sender has a low reputation.
What is SMTP relay, and how does it work?
SMTP relay is a service that helps to send messages on behalf of another email server. It’s used by companies that send large volumes of emails to scale their mailings and continue their email marketing while avoiding spam email filters.
Why should I only email people who have opted in?
Sending too many unsolicited emails is the shortest way to being banned by your ESP.
How to check if your email address is blocked by spam filters
Take a closer look at your main KPIs: deliverability, open rate, and CTR. If they have fallen sharply, you’re likely blocked by your ESP.
