Even the most carefully crafted email campaign is useless if no one ever sees it. With inboxes increasingly protected by intelligent spam filters, marketers face an uphill battle to ensure their emails are delivered and read.
So, how do you beat the spam filters and make sure your emails land where they should?
In this blog, we’ll look at how spam filters work, what they look for, and what you can do to improve your chances of reaching the inbox.
What are spam filters and why do they matter?
Spam filters are automated systems that assess incoming emails to decide whether they’re safe and relevant. They’re designed to protect users from unsolicited, irrelevant, or potentially harmful messages, and they’ve become far more sophisticated in recent years.
So much so, that spam filters are still the biggest barrier for marketers in finding success with email. In fact, marketing professionals cite spam filtering as the biggest barrier to reaching consumers for 60.3% of businesses according to data.
Unfortunately, even well-intentioned email campaigns can be flagged if they share certain traits with spam: outdated data, inconsistent sending patterns, poor sender reputation, or overly promotional language.
Understanding what triggers these filters is the first step to getting past them.
What spam filters look for
Different spam filters have different rules, but most look at a combination of:
- Technical setup: including SPF, DKIM, and DMARC authentication
- Email content: spammy language, excessive formatting, or attachments
- Sender behaviour: volume, consistency, and complaint history
- Engagement signals: how often users open, reply, or click
- Blacklist status: whether your domain or IP has been flagged in the past
Some filters also take cues from user behaviour. For example, if lots of people are ignoring or deleting your emails, that can push future campaigns straight into the junk folder.
8 ways to avoid spam filters and stay visible
1. Set up proper domain authentication
Use SPF, DKIM and DMARC to prove that you’re a legitimate sender. Without them, your emails may appear suspicious to filters and go straight to junk.
2. Use verified, up-to-date data
One of the most common reasons for poor deliverability is sending to outdated or invalid addresses. Work with data that’s been cleaned and verified recently — we do this regularly at Integra to maintain quality and performance.
3. Be careful with your wording
Spam filters are triggered by excessive use of promotional words like “free”, “guaranteed”, “limited time”, or “click here”. Avoid all caps, too many exclamation marks, or flashy formatting.
4. Maintain a steady sending rhythm
Sudden spikes in volume can look suspicious. Whether you’re emailing 500 people or 50,000, build up gradually and send consistently.
5. Make it easy to unsubscribe
It’s better to have someone unsubscribe than to mark your message as spam. A clear unsubscribe link helps protect your reputation and keeps your list healthy. It’s also a legal requirement for PECR and GDPR.
6. Segment and personalise
Sending relevant content to the right people reduces complaints and boosts engagement, two things spam filters reward. Even basic segmentation by industry or role can make a difference.
7. Monitor engagement metrics
Watch your open and click rates, bounce rate, and spam complaints. If you see a dip, take action quickly. A low engagement rate tells email clients that users don’t want to hear from you.
8. Help your audience whitelist you
If you’re ever asked “how do I whitelist an email?”, it usually means your recipient wants to keep your messages out of junk. Encourage subscribers to add your email address to their contact list or safe sender list — this simple action can drastically improve future deliverability.
Additional tip: Test before you send
Many email platforms offer pre-send testing tools to check your spam score. These can flag any red flags before your campaign goes live, giving you a chance to make adjustments in advance.
Cut through the noise (and the filters)
Spam filters aren’t your enemy, they’re just doing their job. The key is to work with them, not against them. If you’re regularly finding your emails caught in junk folders, it’s time to review your technical setup, your data quality, and your messaging approach.
By following best practices and staying consistent, you’ll improve not only your inbox placement but also your overall campaign results. And if you’re ever in doubt, ask your audience to whitelist you, they might be wondering “how do I whitelist an email?” themselves.
Small changes, big impact. Especially when your message finally lands where it matters.
Good marketing starts with great data, and great data starts with data cleanliness. If you’re not sure where to start, let’s have a conversation. Get started by filling out the form at the bottom of the page.