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How to Avoid Spam Filters When Sending Emails in 2023

27 min read
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Cold emails are key to creating a successful outbound sales strategy. 

However, with the rise of spam, phishing, and other malicious emails, most email providers have powerful spam filters to protect users’ inboxes.

While these filters are great at catching unwanted messages, they can sometimes block your legitimate emails from reaching your prospects’ primary inboxes.

And if your emails end up in spam folders, it can significantly impact your ability to reach customers and achieve your sales goals.

The good news is you can follow some smart tactics to avoid spam filters and ensure your messages get delivered.

How to Avoid Spam Filters – Table of Contents

What Are Spam Filters?

Spam filters are programs that automatically detect and identify unwanted, harmful, and virus-infected incoming emails. They place these such emails in your spam folder instead of your primary inbox.

These filters use various criteria to identify spammy characteristics in incoming emails and send them to a designated “spam” or “junk” folder. In some cases, they even add a warning tag.

What’s more, these filters can also analyze the content of incoming messages. Based on the analysis, they allow valid emails to reach the primary inbox while filtering unwanted or harmful messages into the spam folder.

3 Reasons Why Your Emails May End Up in the Spam Folder

When your emails end up in the spam folder, it can be frustrating. 

We’ve all been there — you send out a carefully crafted email, only to have it wind up in your prospect’s spam folder. 

Here are the main reasons that may have been causing your emails to be placed in your prospects’ spam folders.

Reasons why emails go to spam folder

Reason #1 – You Have a High Spam Complaint Rate

If a lot of prospects are manually marking your emails as spam, email providers will take notice. 

Their spam filters specifically look for senders and domains that generate high complaint rates and automatically reroute such emails to the spam folders.

This usually happens when your email content is irrelevant or otherwise seen as low-value by your prospects. 

For example, if you’re sending mass emails with generic content to purchased email lists, many of your prospects are likely to complain. As a result, your sender’s reputation is likely to suffer. 

That’s why it’s crucial to ensure that your emails are tailored and relevant to each prospect if you want to avoid spam filters. You should also include clear sender information and an easy-to-spot unsubscribe option in each email.

Reason #2 – You Have a Bad Sender Reputation

Major email providers like Gmail maintain large databases of sender reputations. 

They track metrics like complaints, unsubscribes, and spam traps triggered to determine if a sender is trustworthy. 

If your domain or IP address has a history of sending spam or malware, your sender reputation is likely to be low. As a result, your emails are more likely to be labeled as spam.

That’s why it’s important to build a strong sender reputation by avoiding shady practices and sending only legitimate emails to relevant prospects. 

It’s also a good practice to regularly monitor your inbox placement rate and spam complaints. This way, you can spot and fix issues with your campaign early on.

Reason #3 – Your IP is Blacklisted

There are several third-party IP blacklists that identify known sources of spam and blacklist such IP addresses. These blacklists are continually updated based on spam complaints, honeypot traps, and other signals. 

If your outgoing IP address ends up on one of these lists, it can essentially send your (even legitimate) emails to the spam folder.

So, determine if your IP address is blacklisted, find which lists blocked you, and get it removed.

Once it’s done, we recommend that you also read up on the best practices for email deliverability.

It will help you to avoid future blacklisting and maintain build a solid sender reputation over time.

15 Proven Ways to Avoid Spam Filters

Email is a powerful tool for businesses to reach existing as well as potential customers and drive sales.

However, it’s super annoying when your important emails end up in the spam folder. Getting your emails successfully reach your prospects’ primary inboxes is crucial for launching successful campaigns.

Fortunately, there are several proven ways to prevent your emails from going to the spam folder.

1. Familiarize Yourself with International Spam Laws

If you want to learn how to avoid spam filters, you should start by learning more about international spam laws across the globe.

Many countries and regions have anti-spam laws that you must abide by when sending cold emails. These laws are meant to protect the residents from spammers. 

And if you don’t comply, you may end up paying hefty fines. 

Here are the most important anti-spam laws you must always comply with:

  • The CAN-SPAM Act — The CAN-SPAM Act requires all email senders to include their physical address, not use misleading information, and make it easy for prospects to unsubscribe from the email lists.
  • Canada’s Anti-Spam Legislation (CASL) — According to the CASL law, all email senders must first get permission from prospects to send emails to them.
  • General Data Protection Regulation (GDPR) — The GDPR Act, or General Data Protection Regulation, requires companies to obtain explicit consent for collecting and handling user data. It makes it easy for users to opt-out if they want.

2. Use a Credible Email Service Provider (ESP)

Email service providers (ESPs) play a crucial role in email deliverability. Major ISPs and email providers like Gmail use advanced spam filters to block unwanted and suspicious emails. 

If your emails are being sent through an unknown or disreputable ESP, the risk of those emails being flagged as spam increases significantly.

On the other hand, when you use a well-known and credible ESP, you benefit from their reputation. Established players in the industry have put in the work to build relationships with major ISPs and ensure their IP addresses and domains are recognized.

Plus, credible ESPs always stay on top of changing spam filter algorithms and have an optimized technical infrastructure and long-standing deliverability expertise. 

3. Setup Secondary Domains

If you’re planning on launching long-term, high-volume cold email campaigns, we highly recommend using secondary domains.

If you send all your campaigns through your primary domain, ESPs may throttle or block that domain if the volume seems suspicious.

That’s why it’s essential to set up secondary domains and rotate their use for email sending. This can help you distribute your email volume and avoid crossing sending thresholds that trigger spam filtering. 

In addition, using multiple secondary domains also allows you to maintain deliverability. For example, if your primary domain is, you can get secondary domains like,,, and so on. 

This way, if one of your secondary domains ends up on a blacklist, you can simply switch to sending emails using a different secondary domain.

With Saleshandy, you can connect unlimited email accounts from your secondary domains.

Plus, you can rotate them automatically using the Sender Rotation feature. The only thing you need to take care of is that all your secondary domains have proper email authentication.

That brings us to our next point.

4. Authenticate Your Email Domain

When you send unauthenticated emails, it often raises red flags for spam filters. 

But when you authenticate your email domain, you build trust with email service providers (ESPs) and improve your sender’s reputation.

Ideally, you should set up the following DNS records:

  • SPF (Sender Policy Framework)
  • DKIM (DomainKeys Identified Mail)
  • DMARC (Domain-based Message Authentication, Reporting & Conformance)

Here’s how you can set up each record for authenticating each of your secondary email domains:

SPF (Sender Policy Framework)

SPF is an email authentication protocol that helps you define the list of mailing servers to use from your domain. 

If you want to set up SPF, you need to add a special TXT record in your domain’s DNS settings from your hosting provider or domain registrar like GoDaddy, Google, Zoho, or others.

Here’s how:

  • Create a new record with the type, “TXT.”
  • Write the record’s name as the hostname or prefix without the domain name. You can enter @ or a prefix, such as mail, to place the record on your root domain.
  • In the value field, enter the SPF rule to be applied, such as v=spf1 mx -all (it can be different for different providers), indicating emails are only allowed from your mail server. 
  • Keep TTL at default settings.
  • Save the record.

DKIM (DomainKeys Identified Mail)

DKIM helps confirm that an email actually came from the domain it claims to be from.

To set up DKIM, you need to add a TXT record to your domain’s DNS settings. This record contains a public key unique to your domain.

When your domain sends emails, the emails are “signed” using the private key that matches this public key.

The email prospect can then use the public key to verify the signature, confirming the email really did come from your domain.

Here’s how you can add a DKIM record:

  • Create a Text “TXT” or “CNAME” record per your hosting provider standards.
  • Paste the value or setting for DKIM (from your hosting provider).
  • Set your host in the given format: “is s1._domainkey” where s1 is the DKIM selector. 
  • Click on the Save button. 
  • You can check whether your DKIM has been published successfully or not from here.

DMARC (Domain-based Message Authentication, Reporting & Conformance)

DMARC works together with SPF and DKIM to determine the authenticity of an email message.

For example, SPF checks if a particular email comes from an authorized server. DKIM checks that the email has a valid digital signature. DMARC lets you set a policy for what happens if either of those checks fails.

For example, you can tell your email provider to reject or quarantine messages that fail SPF or DKIM checks.

This gives you more control over unauthenticated emails claiming to be from your domain. 

Here’s how you can set up a DMARC record:

  • You need to add a DNS TXT record or modify an existing one by entering it in the TXT record for “_dmarc:”
  • In the first field of the TXT record, enter “_dmarc.[].”
  • In the second field, enter the text for your DMARC record.
  • Depending on your DNS provider, the field names for DNS TXT records may vary for different providers. 
  • Save your changes.

5. Use Multiple Email Accounts

When sending a high volume of emails from one email account, even from a secondary domain, you’re more likely to trigger spam filters.

That’s why it’s crucial to set up multiple email accounts to distribute your email-sending volume. You can use each email account to send emails to a segment of your email list. 

Plus, when you rotate multiple email accounts to send emails, it prevents you from surpassing daily email-sending limits. This will help you to maintain high deliverability and avoid temporary blocks on your email account.

6. Send Only 50 Emails Per Day from Each Account

As mentioned earlier, sending high volumes of emails from a single account is likely to trigger spam filters or lead to the account being blocked. Email providers place daily sending limits on accounts to combat abuse.

This is why you should limit each account to only 50 emails per day to stay well below the daily sending limits. 

Once you’ve built a consistent sending reputation over several weeks, you can begin gradually increasing your email-sending volume each day. 

Gradually increasing your email-sending volume allows spam filters to recognize you as a legitimate sender, rather than a potential spammer who sends a large number of emails all at once.

Here’s a simple calculation to send up to 10,000 emails per day:

sending 10000 emails calculation

7. Warm Up Your Email Account

When you’re starting out, it’s best not to start sending large volumes of emails. Instead, you should warm up your email accounts over 2-4 weeks to establish your IP and domain as trusted senders.

The best approach is to send just 5-10 emails the first week to a small test segment. Then, monitor how these initial test emails perform. 

If they are well-received and don’t trigger spam filters or high unsubscribe rates, you can gradually increase your sending volume while maintaining email quality and engagement. Throughout the process, pay close attention to delivery rates, opens, clicks, and other metrics.

Once your warm-up sequence achieves good inbox placement, your account is ready for larger campaigns.

8. Create a Verified Email List

Another strategy to avoid spam filters and achieve good deliverability is to create a verified email list. 

When you send emails to invalid or inactive contacts, it can increase your bounce rate and reduce engagement. This reflects poorly on your sender’s reputation.

That’s why it’s critical to invest the time upfront to build a verified list of prospects’ email addresses.

Beyond improved deliverability, sending emails to verified and relevant prospects also boosts open and response rates. 

9. Write Engaging Subject Lines

The subject line is the first thing that prospects see before deciding to open an email. An engaging subject provides clues that your email is legitimate and worth reading rather than spam.

In a way, it sets the tone for how your message will be perceived – either as valuable content or as a low-quality spam blast.

That’s why you must write personalized and engaging email subject lines that demonstrate relevance and give your prospects a reason to open your email.

Plus, when you write engaging subject lines, it can also improve your open rates. This, in turn, further improves the deliverability of your future emails by signaling to ESPs that your prospects find your messages worthwhile.

10. Personalize Your Emails for Each Prospect

If you want your prospects to open and be interested in your emails, you need to personalize them. 

When you tailor your messages for your prospects, it shows that you understand who they are and what they need.

Adding some small details, like the person’s name, where they work, their job title, or other details from previous conversations, makes it clear that you’re not sending a generic message. 

It shows you’ve done your research because you genuinely want to connect with them.

You can use merge tags in your email content to add this level of personalization. 

Think of merge tags as placeholders/variables to represent contact data for each prospect in your email list. Using these tags, you can insert dynamic content tailored to your different target audiences. 

Beyond email deliverability, email personalization also boosts other metrics including the engagement rate. 

When prospects find content in the email that resonates with them personally, they are more likely to click on links and respond to calls to action. 

11. Include an Unsubscribe Link

Another important thing you can do to avoid spam filters is to include an unsubscribe link at the bottom of every email you send out. 

If someone wants to opt out, you should respect their choice. 

Ideally, the unsubscribe link should be easy to spot so that your prospects can opt-out with just one simple click.

After that, you should completely remove them from your contact list or database within 48 hours.

unsubscribe link in email

If you don’t remove people who have requested to opt-out from your list, they’re highly likely to flag your future emails as spam. 

As we discussed earlier, many countries also have laws that make it easy for users to unsubscribe. If you don’t follow these laws, you may have to pay a hefty fine or face other legal problems.

So, be sure to promptly take people off your email list when they unsubscribe.

In a nutshell, making it easy to unsubscribe is good for open rates, deliverability, and long-term sender success. And, it is also a legal requirement in various countries and regions around the world.

12. Keep an Appropriate Interval Between Emails

Spam filters often look at the sending patterns of email addresses. 

If you suddenly send a massive volume of emails after long periods of inactivity or send irregularly, it can trigger suspicions and potentially lead to your emails being flagged as spam.

But when you consistently send valuable, non-spammy content to your prospects, you can build a positive sender reputation.

So, if you stick to a regular and predictable sending pattern, your prospects and the email service providers will see you as more reliable and trustworthy. 

As a result, your email deliverability will get better over time when you send a predictable number of emails on a steady schedule.

13. Maintain a Strong Sender Reputation

Sender reputation matters to avoid spam filters because it’s like your email trust score. A good score means your emails land in inboxes; a bad one means they go to spam.

Factors like how often people engage with your emails, the number of complaints, and how consistent your sending practices are all affect your reputation. 

If you have a history of being seen as a trusted sender, the email providers are less likely to stop your messages from going through.

Some ways to improve your sender reputation are:

  • Avoid sending emails to prospects who have unsubscribed from your contact list. This helps prevent complaints about spam. 
  • Make sure your emails provide useful content that people want to receive.
  • Set up email authentication records like SPF, DKIM, and DMARC to confirm you’re a valid sender.
  • Monitor which emails bounce or get marked as spam. Remove invalid addresses from your lists.
  • Keep your mailing lists updated and segmented so that your prospects get relevant content.
  • Write quality email content that engages your prospects. This will help to improve your open and click rates.
  • Maintain consistent and moderate sending volumes, frequency, and schedules.

By building a good sender reputation over time, your emails are less likely to be blocked or filtered as spam.

14. Keep Your Image-to-Text Ratio Low

Spam filters tend to block emails containing mainly images and little text. If you want to prevent your emails from being spammed as spam, make sure to keep your image-to-text ratio low. 

The reason is that spam filters are more likely to flag emails with a high image-to-text ratio. 

Ideally, you should only use images to visually support or enhance the textual content. If you have to include images, you must write clear text descriptions for any images, charts, or graphics you insert so readers understand them.

Keeping your emails text-heavy and using images sparingly prevents spam filters from seeing them as suspicious. The textual content makes your messages searchable and scannable too.

15. Use a Reliable Email Outreach Tool

Using a reliable email outreach tool can help prevent your messages from being blocked or filtered as spam.

Ideally, the right email tool will have features to help build your sender reputation and avoid triggers that get emails flagged.

Here are some key features to look for in email outreach tools:

  • Connect unlimited email accounts
  • Integrations with major ESPs to maintain good sending reputations across providers
  • Auto follow-up and scheduling features to control send volume and frequency
  • Customizable templates to create professional, engaging content
  • Analytics on opens, clicks, and unsubscribes to optimize campaigns

Choosing a tool that offers these features can not only help avoid spam filters when sending emails but also take your email outreach game to the next level.

For example, you can consider using Saleshandy, a leading cold email outreach tool, that allows you to send automated emails at scale with high email deliverability. 

Here are the unique features of Saleshandy that make it the number-one email outreach tool:

  • Email Ramp-Up – The Email Ramp-Up feature lets you gradually increase the number of emails you send over time and avoid overwhelming your prospects while also avoiding spam filters and improving your deliverability.
  • Auto Follow-Up – If some of your prospects don’t respond to your initial email, you can use the Auto Follow-Up feature to automatically send follow-up reminder emails to them. It saves you time from having to manually track and send reminders yourself.
  • Sequence Score – Using Sequence Score, you can assess how effective your email sequence is based on your Email Setup, Sequence Setup, Email Copy, etc.
  • Sender Rotation – With Sender Rotation, you can rotate your email accounts randomly to prevent ESPs from flagging your emails as spam.
  • A-Z Testing – You can use the A-Z Testing feature to create 26 different versions of your emails and test all variants to see which one performs the best in terms of email deliverability and engagement.

Watch the following video to learn how to use Saleshandy to send successful automated email campaigns.

Best Practices to Prevent Spam Filters

Spam filters make it hard for your cold email campaigns to reach all your recipients. But if you’re careful, you can avoid the dreaded spam folder.

Here are some best practices you should follow to avoid spam filters:

Best practices to prevent spam filter

Don’t Buy Email Lists

The first thing you should really avoid is buying lists of email addresses to send to. This can cause major issues with spam filters blocking your emails.

The problem is that bought lists often contain invalid or outdated addresses. They also include prospects who may be irrelevant to your business. So, when you send emails to these lists, many people are likely to mark your messages as spam.

If a lot of people report your emails as spam, email providers will start automatically filtering all your messages as junk. This can damage your sender’s reputation and reduce your deliverability.

It’s much better to build a quality lead list rather than buy the list from a third-party vendor. It will help you to create an engaged email list with prospects who are relevant and are actually interested in your emails.

Don’t Send Emails to Bounced Addresses Repeatedly

Another common mistake to avoid is repeatedly sending emails to addresses that bounce back or are no longer valid. This can really hurt your sender’s reputation too.

You see when an email bounces, it means the address is wrong or no longer active. But if you keep trying to send to that same bounced address, ESPs will notice. 

Plus, sending emails repeatedly to invalid addresses looks like spam behavior. It makes spam filters think you are just blindly emailing anyone without caring if the address is real.

So when your emails bounce, you should remove or deactivate that particular email address from your email list to keep it clean and targeted.

Don’t Send Generic Emails

When you’re sending cold emails for the first time, it may be tempting to just blast out the same generic emails to your whole email list. But this is actually not a good approach and can hurt your sender’s reputation and email deliverability.

The problem is that when you send a generic “one-size-fits-all” email, most of your prospects won’t find your content relevant. If your message doesn’t feel tailored to them specifically, they’re highly likely to mark it as spam. 

That’s why you must personalize and segment your emails so each prospect gets a message matching their interests.

For example, you can split your email list based on demographics or prospect type to target different content for each group. You can also use merge tags to include each prospect’s name and other details to make it feel customized.

The important thing to remember is you must take the time to make each of your prospects feel you’re reaching out directly to them.

Don’t Write Misleading Subject Lines

Another mistake you would want to avoid is writing misleading subject lines because they can directly affect your email deliverability.

Writing misleading subject lines may help to trick your prospects into opening your emails but they’ll end up disappointed. And if they get frustrated, they may even report your email as spam.

For example, a subject line like “Your account has been suspended” will likely get opened. But if the email just contains a sales pitch, your prospects will immediately report your email and block you.

So, you should always write accurate subject lines that honestly represent the content of your email.

Don’t Use Spam-Triggering Words

Last but not least, you also want to be careful with the words and phrases you use in emails to avoid spam filters. 

Some spammy phrases can trigger filters.

For example, words like “free,” “act now,” “buy,” “sale,” and “discount,”  are red flags as they are closely associated with spam.

Also, overusing superlatives like “best,” “last chance,” “guaranteed,” or “risk-free” seems aggressive and promotional. Spam filters pick up on these words.

So, what you should do instead is focus your copy on sincerely communicating value without hype or pressure. 

Reach Your Prospects’ Inboxes Successfully

As you have learned, you can avoid spam filters if keep the above-mentioned best practices in mind and deliver them successfully to your prospects’ primary inboxes.

Just remember one thing – spam filters have evolved a lot and are smarter than ever. So, you need to be genuine with your email content and deliver real value.

If you follow the tips mentioned in this post, your emails are likely to avoid spam filters.


1) Why do emails go to spam instead of inbox?

If your emails are going to spam instead of inbox, it may be because spam filters are flagging your emails as suspicious. This can happen because your sender address looks fake, you are sending a lot of emails at once, the content is irrelevant to your prospects, or your email account has been compromised.

2) What triggers email spam filters?

Several reasons can trigger spam filters, including suspicious or unauthenticated email addresses, spam trigger words, excessive links, questionable attachments, or irrelevant generic content.

3) What can help to avoid email spam filters?

If you want to avoid email spam filters, you must use reputable ESPs like Gmail or Outlook, authenticate your email domain, and personalize email content for each prospect.

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