If you’re putting the time and energy into email marketing, the last thing you want is the fruits of your labor landing in the spam folder. Unfortunately, if you don’t know much about how spam filters work, you may unintentionally be sending emails that your subscribers never see.
You can ensure that your audience receives your emails by understanding how spam filters work and utilizing best practices to avoid being flagged by them. Avoiding the spam filter will result in more effective email marketing that benefits your bottom line.
How Do Spam Filters Work?
According to Statista, in 2021, nearly half of all emails were spam. Because of this high volume, email providers each set different types of spam filters to protect against unwanted and unsolicited bulk mail and malicious content.
According to Mailchimp, different filters weigh each spam factor and add them up to assign a spam score, which determines whether a campaign will pass through the filter. When the score exceeds a certain threshold, the email is marked as spam and is sent to the junk folder or rejected and not delivered.
Email spam filtering typically measures:
- Whether the sender’s email address or domain is denylisted
- The presence of spam trigger words
- Number of links and whether they direct to suspicious websites
- Engagement rate (based on previous emails sent)
The list of spam criteria is continually growing and adapting based on what people identify as spam in their inboxes. Spam filters look at the sender, language patterns, etc., of emails that users mark as spam and then establish rule-based filters. When one of your subscribers marks an email as junk or spam, it’s unlikely that your future emails will reach them.
How to Avoid the Spam Filter
There’s no magic formula to bypass the spam filter, but there are best practices that will help ensure your email marketing is not accidentally flagged as spam. We identified seven key practices to help you avoid the spam filter:
- Be mindful of your subject lines
- Remember the technical stuff
- Maintain a healthy email list
- Take care of the email body
- Utilize spam checkers for feedback
- Monitor your email engagement
- Don’t be annoying
1. Be Mindful of Your Subject Lines
Studies have shown that most people mark an email as spam based only on the subject line. Mailchimp recommends short, descriptive subject lines without too much capitalization or punctuation (i.e., too many exclamation marks) to avoid being perceived as spam.
Additionally, you shouldn’t use misleading subject lines that don’t match your email content. If you make false promises in your subject line and don’t deliver, users are likely to mark your email as spam.
Certain words in subject lines (i.e., “cash,” “free,” “winner,” etc.) may be blacklisted because of their association with spam emails. If your email happens to make it past the spam filter, it still might seem suspicious to your audience if you use overly-spammy language.
Try asking a question in your subject line instead of using marketing lingo or unusual formatting to stand out in the inbox. It may also help to use a recognizable sender name.
2. Remember the Technical Stuff
Email authentication confirms to providers that you are who you say you are and that your emails are legitimate. There are multiple ways to authenticate your email, including:
- Sender Policy Framework (SPF): This confirms your identity by comparing the sender’s IP with a list of IPs authorized to send from that domain.
- Domain Keys Identified Mail (DKIM): This authentication ensures that email is not tampered with during the transmission/sending process.
- Domain-Based Message Authentication, Reporting & Conformance (DMARC): This authentication requires both DKIM and SPF in order to send and deliver mail.
In addition to authenticating your email, you should choose an email service provider with reliable deliverability. You can also instruct your audience to safelist your email address or add you to their contacts to improve your deliverability.
3. Maintain a Healthy Email List
Avoiding spam filters starts with sending your emails to the right people. You should never purchase an email list because many purchased or scraped lists include bad addresses that lead to higher bounce rates. Always choose to build your own email list. Additionally, providing a double opt-in for your subscribers ensures everyone on your list gave you permission to email them.
Over time, it’s important that you maintain a healthy list. You should send emails regularly so that your list doesn’t grow stale. If you send an email after many months of nothing, it’s more likely to be marked as spam.
You should remove hard bounces from your email list and attempt to reengage inactive subscribers. As a result, you may boost your engagement and provide a positive signal to spam filters.
4. Take Care of the Email Body
Just like your subject lines, the contents of your email could be sending red flags to spam filters. Pay attention to these details in the body of your email:
- Avoid linking to suspicious websites or stuffing too many links into the email.
- Avoid including attachments because these are highly suspicious to spam filters. Instead, try linking to a page on your website where they can download the attachment.
- Use images correctly. Be sure they are sized appropriately and that you aren’t using them as a substitute for text.
- Use correct spelling and grammar. Mistakes can make you look untrustworthy to customers and spammy to email providers.
5. Utilize Spam Checkers for Feedback
If you’re curious about the quality of the email you are sending, run it through the free Mail Tester. This tool checks your email for technical issues with your email deliverability.
Once you’ve sent your test email, you can use the results to inform any changes and improvements.
6. Monitor Your Email Engagement
Low open rates might signal to ISPs that your subscribers don’t want your emails. This could result in fewer of your emails being delivered because they do not pass the spam filter. It’s important to keep your eye on various email engagement metrics. It would be best if you considered monitoring:
- Spam Reports: To keep your subscribers from marking your emails as spam, you should set expectations for email frequency and provide them with valuable content they really want to see. Only email subscribers who have opted-in to receive email from you.
- Your Sender Reputation: A poor reputation will make it harder for you to reach inboxes. Some email providers monitor reputation for you, but you can also use free tools like Sender Score to check on your own.
- Click-Through Rates: The CTR shows you how many people click the links in your email. This is a good indication of if you are providing content that interests your audience. Optimizing this stat can help you hone your email marketing strategy.
- Open Rates: If you notice low open rates, it may help to revive your subject lines or reevaluate your email frequency.
If you are unable to reengage inactive subscribers, it may be in your best interest to remove them from your list. Doing so ensures they do not weigh down your engagement metrics and negatively affect your sender reputation.
7. Don’t Be Annoying
The best way to avoid spam filters is to avoid spammy content. Even if you avoid spam-trigger words and utilize a spam checker, your audience may perceive your email as marketing spam if you are cluttering their inbox with messages they do not care about.
You should never be sending emails just to send them. Be sure that you are offering relevant, valuable content that engages your audience. Instead of sending massive blast emails (a tactic often used by spammers), try to segment your audience into smaller groups and send them more personalized content on a regular basis.
Ask your subscribers to choose products or topics that they are interested in so that you can create valuable content that they want to see.
Get More Email Advice
For marketing tips specific to your business – including email, social media, and digital advertising – contact our team. We’re happy to discuss your goals and possible strategies to help you grow your business.