You won’t wish for your precious belongings to end up in dark, secluded, or dirty places. Your precious emails too need to find their correct destination - the inbox, but often find themselves in the spam folders. So, how to avoid email going to spam?

According to numbers, 160 billion spam emails are sent every day, with 46% of the 347 billion daily emails sent, considered spam (numbers recorded for 2023). 

Think of times when you receive emails related to winning lotteries, mysterious coupon codes, a too good to believe offer, and whatnot. The first instinct is - to not open such emails at all. The fear also comes from security threats these spam emails carry with themselves. 

However, are all emails spam? No. But most of the email service providers today have set up stringent policies to ensure that their users are protected from these spam emails. Hence, they sometimes end up marking a legitimate email as spam too.

Thus as marketers, it is a challenge to create and send emails while figuring out how to avoid email going to spam.

In this write-up, I will share 12 tips to help you avoid the spam folder. We will also dig deeper into how exactly the spam filters work and why emails are landing in spam. 

It is going to be long-read, so keep sipping your coffee. 

12 Tips On How To Avoid Email Going To Spam

When you wonder how to avoid email going to spam - you’re mostly thinking from one perspective only – a poorly written email copy and use of spam words in the subject-line. It is true, undoubtedly. But it is not the sole reason why your emails are landing in spam. There are various elements of your email infrastructure that can lead to email deliverability issues. 

Let’s look at each element affecting email deliverability, from sender reputation to content quality and engagement tracking.

Build a strong sender reputation

To have impeccable email deliverability, sender reputation can be your ally.

Let’s take a few steps back and first understand - how and why sender reputation matters. 

When you are sending emails - whether cold or promotional emails from a domain, the ESPs are always on a lookout for domains that look suspicious or raise red flags. 

This is way more serious when you’re sending a cold email - because the recipient doesn’t know you or has not opted for receiving emails from you. So, deliverability becomes trickier. 

Now what are these red flags that ESPs look out for in domains? It can be your spam complaint rate (the number of people who reported your email as spam); your inbox placement rate (how many of your emails landed in the inbox or primary folder); hard bounces (number of emails that bounced back due to permanent issues); and more similar reasons. 

Remember, building a reputation takes time, but ruining it is quite easy. 

That’s why at Smartlead, we recommend email warmups, especially for new domains, so that you can gradually build up your domain reputation with ESPs.

Build a lead list from scratch

Your lead list is the list of recipients or prospective customers you want to send emails to. 

Now, either you can build this list from scratch, like by collecting email IDs via LinkedIn outreach or tools like Clay or Listkit, or you can purchase lead lists (NOT recommended at all). 

The problem with purchased lead lists is - they are not your target audience. They are just some random email IDs which may or may not be your ideal customers. Some of these email IDs may not even exist in real or may have been changed due to people switching jobs or countries. Mailing them means your emails getting lost or bounced back - hurting your sender reputation.

Organic methods of growing your email list are always better than purchasing or scraping leads. 

When you build a list from scratch, you’re getting people who are genuinely interested in your business. 

Build Domain/IP reputation

If you use a shared IP address to send cold emails - it can badly hurt your reputation.

Using a dedicated IP address or domain for your emails can help you control your email reputation. 

Sharing an IP with others means their bad practices could affect your reputation. 

By having your own, you ensure that only your sending habits are judged. 

However, as we covered in the first tip, simply having a dedicated IP isn’t enough—you also need to keep it “clean” by reducing spam complaints and maintaining high engagement rates. 

This will help prevent your emails from being flagged by spam filters.

Email Authentication

Email authentication acts as your verification badge. 

Methods like SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting & Conformance) ensure that your emails aren’t flagged as phishing or spam. 

SPF checks if your emails are sent from authorized servers, DKIM verifies that your emails haven’t been altered during transit, and DMARC ties everything together to protect your domain from spoofing. 

Before you start sending emails, you have to ensure to set up these authentication on your domain.

Personalize email content

While a good domain reputation and email authentication mechanisms help strengthen your email infrastructure - your email content too is responsible for your emails landing in spam.

A grave mistake that new or amateur marketers do is send generic cold emails. This may have worked in conventional cold emails, but now, with stringent spam policies, sending generic emails is sure fire way to get poor email engagement and thus get a poor reputation.

To avoid this, you must personalize your cold emails.

And no, it isn’t just about using someone’s name in the subject line. 

Go deeper—segment your audience and tailor the content based on their interests, behavior, or previous interactions. 

People are more likely to engage with emails that feel relevant to them. To personalize your emails, you need to invest some time in understanding your ideal audience, which is worth every effort if done right.

Avoid spam trigger words in body and subject line

ESPs have mechanisms in place to scan and filter the content of your email for any spam-trigger words. 

They scan your emails for: 

• Spammy Keywords and Phrases: Words like "free," "guarantee," or "urgent" can trigger spam filters, especially if overused.
• Suspicious Formatting: Excessive use of capital letters, symbols, or exclamation marks, and overly large fonts may raise red flags.
• Links and Attachments: Including too many links, using shortened URLs, or attaching files may cause an email to be flagged as suspicious.
• Poor HTML Coding: Incorrectly formatted HTML code, such as mismatched tags or large image-to-text ratios, can trigger filters.

These terms are often associated with promotional or spammy content, and email filters might push your message into the junk folder. 

So, how do you avoid that?

Use clear and honest language that focuses on the value you’re providing. 

Text to image ratio

The text-to-image ratio in email refers to the balance between the amount of text and images in an email’s content. 

It plays a significant role in email deliverability because many spam filters use this ratio to assess whether an email might be spam. Some email providers, like Outlook or Gmail, block images by default, which means recipients might not see important content. This can lower engagement rates, which also hurts deliverability.

While there's no fixed rule, an ideal text-to-image ratio is generally considered to be 60% text to 40% images or even higher text content. 

Monitor engagement rates

Your engagement rates—open rates, click-through rates, and bounce rates—are key indicators of how well your emails are being received. 

If people aren’t opening or interacting with your emails, this means either you’re sending low-value content or you are sending it to the wrong audience. 

If you continue receiving lower engagements, it can hurt your sender reputation. 

Many email marketers these days request recipients to reply to their email to continue receiving email communications from them. Replies show an active engagement and thus ESPs have less reasons to mark your emails as spam.

Utilize spam checkers

One way to check whether your email contains spam trigger words is to run it through a spam checker. 

These tools analyze your email’s content, subject line, and format to ensure nothing triggers spam filters. 

You will get a score that indicates how your email is performing in terms of spam content.  

If you’re looking for a free spam checker, you can explore Smartlead’s Spam Checker Tool. Simply enter your email in the provided space and run the test. 

Here’s an example: 

Ask recipients to whitelist your email address

A simple way to improve deliverability is to ask your recipients to add your email address to their contacts or whitelist you. 

This tells their email service provider that they trust your messages. Check out this article, if you’re wondering how to whitelist an email address in Gmail.

You can include a polite request in your welcome email or at the bottom of your messages. 

This small step can significantly improve inbox placement and reduce the chances of being marked as spam.

Include an unsubscribe button

Always include an easy-to-find unsubscribe button in your emails. 

This might seem counterintuitive, but making it easy for people to opt out can save you from spam complaints. 

Plus, it’s required by law under regulations like CAN-SPAM and GDPR. 

When people can quickly unsubscribe, they’re less likely to report your email as spam, helping you maintain a clean sender reputation.

Watch out for spam traps

Spam traps are email addresses set up to catch senders who aren’t following best practices. These addresses do not belong to any real users. 

There are two main types of spam traps:

1. Pristine Spam Traps: These are email addresses that have never been used by a real person and have never signed up for any newsletters. They are often published in hidden ways on websites, so anyone sending to them is likely scraping email addresses or using unverified sources.
2. Recycled Spam Traps: These are old email addresses that were once valid but have been abandoned and repurposed by email providers. If someone is sending emails to these addresses, it indicates that they are using outdated or unclean email lists.

Spam traps are similar to honeypots. However, Honeypots are decoys used to lure attackers into a trap. In the context of cybersecurity, they’re set up to detect and track malicious activities, such as hacking attempts or spam bots. 

Sending to a spam trap or honeypot can damage your reputation quickly. 

To avoid them, always clean your email list and focus on sending to engaged, active recipients. Regularly prune your list to remove inactive or bouncing addresses.

How to Avoid Emails Going to Spam in Different Mailbox Providers

We have seen some common grounds on which ESPs can mark your emails as spam. 

Now, let’s look at some ESP specific reasons to learn how to avoid email going to spam. 

Gmail

Gmail’s spam filters are tough to crack. They use advanced machine learning and AI to analyze every email. 

Gmail looks for specific criteria, and if your email matches too many red flags, it’s a one-way ticket to the spam folder. 

Here are some common reasons Gmail might mark your email as spam:

• Sending emails to unengaged users
• Blacklisted email or IP address
• Malicious links
• Using spam trigger words
• Poor sender reputation
• Sending unsolicited emails
• Mixing content types
• Impersonating other domains

How to Pass Through Gmail’s Spam Filter

• Warm up your emails: Start by sending smaller warm up emails to engaged users and gradually increase your sending volume. This helps build a positive reputation with Gmail’s filters.
• Ask recipients to add you to their contact list: Encourage your subscribers to add your email address to their contact list or whitelist you. This increases the likelihood of your emails landing in their inbox.
• Don’t send to unengaged users: Regularly clean up your email list to remove inactive or unresponsive recipients. Sending to disengaged users can hurt your reputation and increase the chances of landing in spam.
• Use spam checkers: Before sending, run your emails through spam-checking tools to catch any red flags that could trigger Gmail’s filters. This will help you fix issues before they affect your deliverability.
• Set up email authentication: Implement SPF, DKIM, and DMARC to authenticate your emails. These protocols show Gmail that your emails are legitimate and haven’t been tampered with, boosting trust in your domain.
• Avoid spam reports: Spam complaints on Gmail can quickly ruin your sender reputation. Always focus on sending relevant, valuable content that people want to receive.
• Simplify your HTML and limit URLs: Avoid excessive use of HTML or multiple URLs in your emails. Gmail prefers emails that have a balanced mix of text and visuals. Aim for a text-to-HTML ratio of about 60:40, with 60% of your email being plain text.
• Stay clear of blacklists: Regularly monitor blacklists to ensure your domain or IP address isn’t flagged. Getting blacklisted can cripple your deliverability in Gmail.
• Test your emails: Before you hit send, always test your email to see how it looks and whether it passes Gmail’s filters. You can do this by sending test emails to various inboxes or using tools designed for email deliverability testing.

Microsoft Outlook/hotmail or Microsoft 365 Outlook (previously Office 365 users)

Microsoft Outlook’s built-in “Junk Email Filter” serves as the first line of defense against spam, helping users keep unwanted and irrelevant messages at bay. This filter has evolved over time, using more advanced techniques to protect inboxes from being cluttered with spammy or malicious emails.

Outlook’s spam filter works by assessing different factors to determine whether an email should be sent to the junk folder or reach the inbox. Some key factors it evaluates include:

• Sender’s credibility
• Email structure
• Email content

The filter uses a mix of methods like heuristic analysis, which evaluates patterns and behaviors; user feedback, which relies on reports from users flagging emails as spam; and Bayesian filtering combined with machine learning, allowing the system to learn and improve over time by analyzing incoming messages.

How to Pass Through Outlook’s Spam Filter

If you want to ensure your emails avoid the junk folder in Microsoft Outlook, follow these best practices:

• Understand Outlook’s Spam Filter: Get familiar with what Outlook flags as spam. By understanding how the filter works, you can tailor your emails to meet its requirements.
• Use a Trusted Email Domain: Stick to a reliable and authenticated domain when sending emails. This boosts your credibility in the eyes of Outlook and lowers the chances of being filtered as junk.
• Manage Sender Reputation: Regularly monitor and improve your sender reputation. A poor reputation can easily get your emails flagged. Avoid sending to inactive users or those who didn’t opt-in, as this can harm your credibility.
• Clear Subject Lines: Use straightforward, honest subject lines. Avoid sensational or misleading subject lines that could be flagged as spam.
• Monitor Engagement Rates: Keep an eye on open and click-through rates. If your engagement is low, Outlook might start pushing your emails into the junk folder.
• Clean Your Email List: Regularly update and clean your email list by removing inactive users. Sending to a high percentage of inactive or unengaged contacts can raise red flags for Outlook’s spam filter.
• Ask Recipients to Whitelist You: Encourage your recipients to add your email address to their list of safe senders or contacts. This will help ensure your emails always land in their inbox.

How To Know Your Emails Are Landing in Spam

It’s crucial to know whether your emails are reaching your audience’s inbox or being filtered into the spam folder. 

Here are some methods to track email deliverability and ensure your emails land where they’re supposed to:

• Use Seed Lists

A seed list is a set of test email addresses spread across different email providers (like Gmail, Outlook, Yahoo, etc.) that you can send test emails to. By doing this, you can monitor whether your emails are reaching the inbox, landing in spam, or getting blocked altogether. This allows you to catch potential issues early and make adjustments before your campaign goes live.

• Track Engagement Rates

Engagement metrics such as open rates, click-through rates, and bounce rates are clear indicators of whether your emails are being delivered to the inbox. If you notice a sudden drop in these metrics, it could be a sign that your emails are landing in spam. For example, a consistently low open rate suggests that your emails aren’t being seen by recipients, or worse, they’re being filtered out.

• Check Spam Complaint Rate

You can use Smartlead’s free tool to track your spam complaint rate. This tool helps you understand how many recipients are marking your emails as spam. A high spam complaint rate is a strong signal that your emails may be bypassing the inbox and landing in junk folders. Monitoring this regularly is key to maintaining a healthy sender reputation.

Understanding Spam Complaint Rate

Spam complaint rate refers to the percentage of recipients who mark your email as spam. Every time someone clicks the “Mark as Spam” or “Report Junk” button in their email client, it counts as a spam complaint. 

A high spam complaint rate signals to ESPs that your content isn’t welcome in users' inboxes. As a result, ESPs will start filtering your emails into the spam folder to protect their users. Even legitimate emails can end up in spam if too many people mark your past emails as unwanted.

When your spam complaint rate goes up, your sender reputation suffers. 

Understanding Spam Filters and How They Work

Spam filters are the gatekeepers of inboxes, designed to sift through emails and decide which ones make it to the inbox and which get sent to the spam folder. 

These filters use a combination of algorithms, content analysis, and user feedback to classify emails. 

The goal is to protect users from unsolicited, harmful, or irrelevant content.

How Spam Filters Operate

• Algorithms and Machine Learning Modern spam filters use sophisticated algorithms that analyze email patterns and behaviors. With the help of machine learning, these filters continuously improve their ability to detect spam. The more data they process, the better they get at distinguishing legitimate emails from spammy ones. For example, they might learn from users’ actions, such as flagging certain emails as spam or marking them as safe, and adapt accordingly.
• Content Analysis Spam filters don’t just look at who is sending the email—they also dive into the content of the email itself. They analyze elements such as:some text
  • Spam Trigger Words: Words like "free," "urgent," or "guaranteed" are often associated with spam and can raise red flags.
  • Text-to-Image Ratio: Emails with too many images and not enough text can be seen as spammy, especially if the images contain embedded links.
  • Suspicious Links: Filters look for malicious or shortened links, which are common in phishing or scam emails.
  • HTML Structure: Poorly coded HTML or an email with excessive formatting can trigger spam filters, as many spammers use broken code.
• Sender Reputation Spam filters assess the reputation of the sender based on factors like past email engagement, bounce rates, and spam complaints. A poor sender reputation can lead to emails automatically being flagged as spam, regardless of content.

Popular Spam Filters

We have already covered Gmail and Outlook spam filters in the previous sections. Lets look at two more popular ones. 

• Barracuda: Barracuda is a widely used third-party spam filter known for blocking phishing attempts, malware, and spam emails. It integrates with businesses to enhance email security.
• SpamAssassin: SpamAssassin is an open-source spam filter used by many businesses and email platforms. It uses a score-based system to determine whether an email is likely spam based on various factors like content, headers, and sender reputation. 

Stop Emails Going to Spam with Smartlead

Smartlead offers a suite of tools designed to enhance your email deliverability and keep your messages out of the spam folder. 

Here’s how Smartlead can help:

• AI-Powered Email Warmups: Smartlead uses efficient AI-powered email warmups to gradually increase your sending volume. This builds your domain’s reputation over time and helps prevent your emails from being flagged as spam.
• Rotating Sender Accounts and Dedicated IPs: To maintain a positive sender reputation, Smartlead allows you to rotate sender accounts and use dedicated IPs. This reduces the risk of your emails being associated with spammy behavior.
• A/B Testing: With Smartlead, you can A/B test your emails to determine which versions perform better. This helps you refine your content and approach based on real engagement data.
• Personalization Through Clay: Smartlead’s personalization tool, Clay, enables you to tailor your emails to your recipients, making your messages more relevant and engaging.
• In-Built Email Verification: As you create your campaigns, Smartlead’s email verification add-on lets you validate your lead lists within the platform. This ensures you’re sending to clean, active addresses and helps avoid spam traps.

By leveraging these features, Smartlead helps you optimize your email campaigns and improve deliverability, ensuring your emails reach your audience's inboxes.

Bottom-Line

Ensuring your emails reach the inbox rather than the spam folder is essential for effective communication and engagement. 

By understanding the factors that influence spam filters and using tools like Smartlead to enhance your email practices, you can significantly improve your deliverability and sender reputation.

Ready to boost your email deliverability? 

Explore how Smartlead’s advanced features can help you achieve better results with your email campaigns. 

Discover Smartlead’s today and take advantage of our 14-day free trial to experience the difference firsthand. Start optimizing your email outreach and watch your engagement rates soar