Avoid the Spam Filter: Tips for Tech Marketers in 2021

Ahh yes, the dreaded spam folder…where email campaigns go to die. Just the mention of it runs shivers down any marketer’s spine. 

Unfortunately, as much as we would wish it otherwise, 45% of all sent emails are considered spam. That’s not a great statistic for B2B tech companies that want to make a splash and nurture leads through email marketing.

This dire stat begs the question, “How can I execute a deliverable email campaign that keeps me far away from the spam folder?” 

To help you answer this question, we’ve put together a list of tricks and tips. Keep reading for eight actionable spam filter-dodging solutions. 

1. Don’t talk to strangers

As a smart tech marketer, you already know that you shouldn’t be buying lists of “interested prospects” from a third-party source, uploading them to your CRM and then blasting them with unsolicited messages.

But have you (or your sales team!) stopped to think that the “free” list of attendees you get from sponsoring a trade show also falls into that same no-no category?

Both scenarios will get you caught up in the spam filter because people who don’t already know about your company are less likely to open emails and more likely to immediately unsubscribe or report it as spam…which frankly it is if they haven’t opted in.

Not only are unsolicited emails off putting and junk folder fodder, using purchased, borrowed or rented email lists violates HubSpot’s Acceptable Use Policy.

Moral of the story? If they didn’t opt in, don’t email them.

2. Clean unengaged subscribers out of your database

If it’s been awhile since you’ve organized your database, it’s time for some spring (or summer, fall or winter) cleaning.

The goal of your cleaning spree is to find and remove (or simply filter out) inactive subscribers who haven’t engaged with  your emails in the past few months. If you’re like most tech companies we surveyed who send out emails 2-4 times per month, you should reexamine who you’re emailing every 3-6 months. 

Now, you may be asking yourself, “Why is this important? Unopened emails aren’t actually hurting anyone…right?” WRONG. Low open rates are a clear signal to ISPs that recipients aren’t engaged with your emails…and engagement is a big factor in deliverability that can lead to future messages being blocked.

So, who should get the axe from future email marketing messages? We like HubSpot’s graymail criteria…their easy-to-click box can stop messages from getting sent to people who have:

  • Never opened a marketing email from you and hasn't opened the last 11 emails you've sent them.
  • Previously opened a marketing email from you but haven't opened the last 16 emails you've sent them.

You may cringe at the idea of cutting subscribers, but remember—if you’re sending emails to unengaged contacts, your open rates and engagement score will suffer. Plus, with a cleaner email list, you can focus on engaged subscribers who will improve your ROI.

TLDR; Low open rates today = spam filter tomorrow.

3. Avoid spam trigger words

Spam filters become more intelligent all the time, and one of the many ways they judge your email is through its wording. They use a built-in tool to scour your email subject line and body copy for “spammy” words and phrases. If they find any of these words, which we simply call “spam trigger words,” the filters will flag your email and send it straight to the spam folder.

Luckily tech companies aren’t sending out emails with super obvious spam words—like “Viagra” or “Nigerian prince”—but here are some phrases you might be using today that could trigger a spam flag:

  • Apply online
  • Take action now
  • Supplies are limited
  • For you
  • Don’t delete
  • Don’t hesitate

Looking for even more examples of spammy words in emails? Check out this ultimate list of trigger spam words from HubSpot.  It groups trigger words by industry, intent and even parts of speech. 

We recommend that you bookmark this resource for later and use it to compile trigger words relevant to your industry and your email intent (e.g., calls to action), review your current content and adjust your content strategy moving forward. 

PS: Don’t just do it for the algorithm—a whopping 69% of all email recipients report that they can tell by subject line alone whether or not an email is spam.

4. Use images wisely

We all hate the limited fonts (ugh, Arial) and design limitations of HTML emails. That said, while using excessive images (or even embedding the entire email as one large image!) may make your email look better, it is a trigger for the spam filter. 

Why? Because spammers have used this technique for years to embed spam words (see above) as graphics that won’t get picked up by a text reader.

Luckily today spam filtering is based more on sending reputation, but emails with a high image-to-copy ratio may still throw a red flag. Plus, not all email programs are set to download images by default, so your readers may be left with a wonky looking message filled with alt. text.

5. Double check your links

Another trigger that spam filters look for is a mismatched link…where the url typed for text doesn’t match the url it is hyperlinked to.

Maybe you’re thinking, “Why are you telling me this? I would never do that.” We know…but it’s easy to do by accident.

For example, if you type in your company's url (awesome-software-company.com), but the hyperlink it to your product's vanity url (awesome-software-product.com), you could be in trouble.

6. Don’t ghost your subscribers

While you don’t want to annoy unengaged subscribers with a barrage of emails they don’t open, it’s also not a good idea to let your communications lapse for weeks or even months at a time. (Yes, even if you're really REALLY busy.)

If you go dark for a year, then begin emailing people again out of the blue, they will mark you as spam. Why? Simple: because they don’t remember you!

Ghosting and then showing up again randomly also drives unsubscribes...43% of email list unsubscribes come from subscribers who don’t recognize your brand or don’t remember signing up. 

In conclusion, when it comes to your email schedule, be consistent.

7. Don’t send duplicate emails

Are your subscribers not engaging with your emails? Resist the urge to send duplicate emails. Sending duplicate emails is a bit like sending the same text message to an uninterested person over and over again…It might get you blocked.

If you must resend an email to the same contact list—perhaps to send out a reminder email—always make sure to change the subject line and some of the body copy. Otherwise, you’ll surely trigger the spam filter.

8. Partner with outside services to optimize your email deliverability rate

Another great way to dodge the spam folder is by partnering with an outside service provider that specializes in email deliverability.

Companies like SendGrid can optimize your email deliverability through comprehensive services like domain authentication, compliance and deliverability coaching, and proactive ISP outreach.

Also, if you’ve sent at least 400 emails in the last 30 days, you can use HubSpot’s email health tool to analyze your campaign by several metrics, including your spam report rate.


Interested in even more email stats and strategies? Download our free "Email Marketing in the Real World" report to see how your email marketing campaigns stack up against other tech and software companies.

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