How to Avoid Spam Filters? (Triggering Points + Remedies)

What worked to avoid spam filters in 2024 – might not work in 2025.

Why? Because spam filters are evolving.

In fact, some Outlook users (from the receiver’s end) have reported that they missed out on important emails because of spam filters.

This just shows how rigorous these spam filters are.

Various Email Service Providers (ESPs) are rolling out algorithms that counter the spam issue, and hence, marketers have a tough time landing in inboxes.

But here’s the catch.

You can still land in your recipient’s inbox.

From my 10 years of experience in cold emailing, I have achieved nirvana in the context of email deliverability.

I’ll share some of my key strategies to help you avoid spam filters in the most genuine way possible.

How to Avoid Spam Filters? – Table of Contents

• What Are Spam Filters?
• How Does Spam Filters Work?
• Why Does Your Email Go to Spam?
• 15 Tips on How to Avoid Spam Filters
• Guidelines Provided by Google, Outlook, and Other ESPs
• TL;DR – How to Avoid Spam Filters
• FAQs

What Are Spam Filters?

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

How Does Spam Filters Work?

The different email service providers (Google, Yahoo, Outlook) have unique filtering methods, but let me explain it simply. 

Spam filter checks the following aspects before giving a score to your email to categorize it as inbox, promotional, spam, or more. 

• The IP address of the email sender
• Domains and subdomains used
• Authentication of the email address
• Words used in the email content 
• Links attached in the email content

Based on these factors, the ESPs categorize your email messages as Priority, Social, Promotion, and Spam. 

Emails with the lowest spam score are categorized as Priority emails and are landed directly in the inbox.

Why Does Your Email Go to Spam? (5 Major TRIGGERING Points)

When they tell you not to stick your fingers into electrical sockets, it’s for your own safety.

Similarly, Google, Yahoo, Outlook, and many other ESPs have set strict guidelines to protect users from spam.

If you ignore these rules, your email deliverability can be severely impacted.

Here are the 5 most critical triggering points.

1. Misleading or Suspicious Content
2. Poor Sender Reputation (or Sending Emails From Blacklisted IP Addresses)
3. Lack of User Consent for Receiving Your Email
4. Lack of Authentication (Very Important)
5. Unverified Email Lists

1. Misleading or Suspicious Content

Why it triggers: Spammers often use these tactics to grab attention and bypass basic filters.

If you think you are smart, ESPs are smarter. Their advanced trackers detect the intent mismatch and click baits with the help of AI/ML algorithms.

This can happen when your subject line contains salesy content, all caps, unusual character combinations (e.g., $$$), or spam keywords.

One of the biggest red flags is sending an attachment to your first email. This increases the chance of your email falling under phishing.

How can you avoid it? – Write clear, personalized, natural-sounding emails.

2. Poor Sender Reputation (or Sending Emails From Blacklisted IP Addresses)

Why it triggers: This indicates that recipients consistently perceive emails from that source as unwanted, damaging the sender’s reputation.

Sender reputation is like a dossier of your sender accounts.

It’s like whenever you send an email, ESPs check your dossier, and depending on your reputation, your emails have a chance of getting delivered in inboxes.

Factors that decide sender reputation – 

1. Bounce Rates: Percentage of emails that fail to deliver. This happens when there is a mismatch in the receiver’s email addresses, when there is server downtime, or when there is a full inbox.
2. Complaint Rate: Volume of user complaints about an email address or domain

How can you avoid it? – Build trust by gradually increasing email volume and maintaining a clean sending list. (Email warmup tools help in this case)

3. Lack of User Consent for Receiving Your Email

Why it triggers: This happens when the sender disregards user preferences, which increases the risk of being filtered out.

When you send emails without getting prior permission to contact the recipients, it can make them (recipients) feel like their privacy is being invaded.

Also, Many email providers allow users to control which senders they receive emails from. So, when you send emails to recipients who have restricted their inboxes, your email will likely violate their preferences.

How can you avoid? – Get explicit consent from your recipients and adhere to their unsubscribe requests.

4. Lack of Authentication

Why it triggers: The spam detection algorithm thinks that you are trying to disguise the true origin of the email (which is a common tactic spammers use).

Email service providers have strict requirements when it comes to email authentication. This is done to verify the legitimacy of an email message and its sender.

It helps ESPs to ensure that the emails are not forged or sent from unauthorized sources.

Actually, (a few years back), it was relatively easier for spammers to forge email addresses and send emails that appeared to come from legitimate sources. This made it difficult for recipients to trust the emails they received.

How can you avoid it? – You can authenticate your emails with SPF, DKIM, and DMARC.

5. Unverified Email Lists

Why it triggers: Unverified lists often contain invalid or inactive email addresses, leading to high bounce rates.

It does not make sense to send emails just because they are on your list.

You need to double-check if those email addresses exist and if you can receive emails. This reduces your chances of getting a hard bounce and improves email deliverability.

How can you avoid it? – Verify your emails before sending them. Avoid using purchased lists and scraped data.

15 Tips on How to Avoid Spam Filters

I know it can be overwhelming to know about all these spam filters. It’s like the more you know how it works, the more hopeless it seems.

But let me tell you, it’s not that difficult to tackle. You can avoid spam filters with the right practices.

I have tried these things and know they work well. So, see if you’re missing out on any of this.

1. Send Personalized Emails (Dynamically)
2. Check Spam Scores From Email Checkers
3. Improve Your IP Reputation
4. Avoid Spammy Words
5. Verify Your Recipients’ Email Address (Before Sending)
6. Warm Up Your Email Accounts
7. Use Reputable Email Service Providers
8. Authenticate Your Email Domain
9. Build Robust Cold Email Infrastructure (Most Important)
10. Add an Unsubscribe Link
11. Don’t Track Open Rates
12. Keep Your Image-to-Text Ratio Low
13. Dynamically Keep Variable Gap Between Emails
14. Send From Different Email Accounts and Domains
15. Send Only 50 Emails per Day From Each Account

1. Send Personalized Emails (Dynamically)

It’s pretty obvious that you are trying to spam if your every email is the same.

Why? Because every recipient’s need is unique, and your emails need to be tailored.

You need to add more elements that convince your recipients that you have invested time in sending that mail.

How? Let me tell you!

You need to enrich your prospect data with relevant information to create a hyper-personalized cold email that helps you break the ice.

Check out the following video, where we’ve covered some cool ideas that will help you personalize your emails.

2. Check Spam Scores From Email Checkers

This is my ritual now. Whenever I’m about to send emails, I always run the email through spam checkers.

There are tools that help you analyze your emails and give a score based on factors like spammy keywords and sender reputation.

Here are the tools you can use to check, 

• Mail-tester.com
• GlockApps
• Sender Score

If you use Saleshandy, you won’t need to use the above platforms. It will directly give your whole email sequencing a score (which you won’t get anywhere else) like this.

3. Improve Your IP Reputation

A good IP reputation means email providers trust that emails sent from my IP address are legitimate and not spam. 

If you want to maintain a good IP reputation, simply focus on sending high-quality emails to engaged subscribers.

Well, there are two simple ways to improve your IP reputation,

1. Warm up your emails before sending them (covered in detail below).
2. Build genuine trust by ending valuable emails and respecting unsubscribe requests.
3. Make sure your emails are HTML-free.

PS. If your daily email sending number is super high, you can use dedicated IP addresses instead of shared ones. It helps you build a strong reputation. But just be careful because managing a dedicated IP requires adherence to strict email-sending guidelines.

4. Avoid Spammy Words

If ESPs detect that your content is trying to sell something, your email will be thrown into the spam folder.

But it’s actually quite simple to avoid this. What you have to do is avoid certain terms in your email, and you are good to go.

Here’s a list of spammy words you can avoid. Keep checking this list as we keep updating it.

In short, use clear and concise language and send authentic emails that provide genuine value to your recipients.

5. Verify the Email Addresses of Your Recipients (Before Sending)

One thing I ALWAYS do before sending an email – Double check the recipients’ email addresses.

Why is this important?

Well, if I ignore this, then I will end up with hard bounces, and my email deliverability (and IP reputation) will be hit a big hit!!

To avoid this, you can use a cold emailing software that helps you verify your email list before sending.

If you ignore this issue – You will increase the chances of being blacklisted by email service providers.

6. Warm Up Your Email Accounts

If you think that email warm-up is something that you do one time and then forget, then you are wrong!!!

Email warm-up is a continuous process. I’ll tell you why.

Let’s say you warmed up your emails nicely and are sending your emails to 10k recipients in two weeks’ time.

Initially, your emails will deliver nicely, but some might be reported as spam. Eventually, the sender reputation will decrease.

So, to maintain a good reputation, you need to continuously warm up your email accounts. You can reduce the number of warmups after some time (like 1-2 months).

Here is a list of email warmup tools that you can use.

In this short, we have talked about the importance of email warm-ups. Check it out!

7. Use Reputable Email Service Providers

Email service providers (ESPs) play a crucial role in email deliverability. 

Many ESPs like Gmail use advanced spam filters to block unwanted and suspicious emails. In case your emails are being sent through an unknown or disreputable ESP, your emails are at the risk of being flagged as spam.

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

Plus, credible ESPs always have a soft spot even if there are changes in spam filter algorithms.

Why? Because they have an optimized technical infrastructure and long-standing deliverability expertise.

8. Authenticate Your Email Domain

You CAN’T MISS this.

Because many ESPs have updated their spam-detecting algorithms and shared guidelines. And they highlighted one thing in common – Email Authentication.

Ideally, there are three DNS records you need to have,

1. SPF (Sender Policy Framework) ➜ It tells ESPs about the servers that are authorized to send emails on behalf of your domain. 
2. DKIM (DomainKeys Identified Mail) ➜ This acts like a digital signature to your emails
   (ie. it verifies and validates your email’s origin and integrity). 
3. DMARC (Domain-based Message Authentication, Reporting, and Conformance) ➜ It acts as an extra layer of protection.
   (Its role is to instruct email providers on how to handle emails that fail SPF and DKIM checks)

Once your DNS records are sorted, you don’t have to worry about getting flagged from the authentication part again.

9. Build Robust Cold Email Infrastructure (Most Important)

Why set up cold email infrastructure?

Because it helps you avoid spam filters while saving you time.

Let me tell you how,

Step 1 ➜ Pick your preferred cold email software (I recommend Saleshandy)
Step 2 ➜ Create your personalized cold email
Step 3 ➜ Connect your email around and start warming them up
Step 4 ➜ Add your sending list and verify the emails
Step 5 ➜ Schedule your emails and track the performance

It’s a one-time setup.

In the following video, we explain how you can send multiple emails every day while ensuring that they land in the recipient’s inbox.

10. Add an Unsubscribe Link

There’s one thing I always make sure of – I never forget to include a clear and easily accessible unsubscribe link.

This is not only a legal requirement in many countries but also a fundamental principle of ethical emailing.

Just remember, whenever you add an unsubscribe link, you need to remove uninterested subscribers and recipients who have consistently had zero engagement.

This will help you improve email deliverability, reduce bounce rates, and ensure that your messages reach the right audience.

11. Don’t Track Open Rates

I know – I know. It’s very tempting to track open rates and measure email campaign performance.

But I advise you to avoid tracking using pixels (especially for cold emails). 

Open rate tracking involves inserting a small image into your email. When the image loads, it signals your system that the email has been opened.

In this case, here’s what I do to track performance and avoid spam filters.

Instead of relying heavily on open rates, I focus on more meaningful metrics like reply rates, click-through rates (CTR) on calls to action, and conversion rates.

These metrics provide more accurate data on campaign effectiveness and engagement.

12. Keep Your Image-to-Text Ratio Low

Avoid sending images or videos in your first email.

I have seen people complaining on Reddit about low deliverability when they have a lot of images in their emails.

Emails with images are problematic because of three primary reasons,

• Email clients may block images by default
• Accessibility issues
• Spam filters may flag them (Because why would anyone send a lot of images to multiple unknown recipients?)

So, I try to avoid these issues and prioritize text content. I use images only when it’s absolutely necessary.

13. Dynamically Keep Variable Gap Between Emails

It’s a red flag if all your emails are sent at the same time (even at the same interval).

Because it seems that a bot is at work.

So, to avoid this, I send emails at fixed intervals, and I use a dynamic approach.

For example, instead of sending emails every Tuesday at 10:00 AM, I might introduce slight variations, such as sending emails with 30 to 90 second intervals in between each email sent (automatically).

This creates a more natural and less predictable sending pattern, making it less likely to trigger spam filters.

14. Send From Different Email Accounts and Domains

Now this practice is to avoid your primary domain from getting flagged by ESPs.

Here’s what I do.

I diversify my sending practices by using multiple email accounts and domains for my cold email campaigns.

For example, I might use variations of my company domain, such as ‘anil@saleshandyhq.com‘ instead of ‘anil@saleshandy.com’.

To know more, check out how to set up secondary domains and email accounts.

This approach helps you in two ways,

• Distribute risk: If one of your email addresses or domain experiences deliverability issues, it won’t negatively impact all of your outreach efforts.
• Improve deliverability: By rotating sender addresses and domains, you can reduce the chances of being flagged as a consistent spammer by email providers.

15. Send Only 50 Emails per Day From Each Account

If you send a large volume of emails from a single account in a short period, it can raise red flags.

So, to maintain a healthy sender reputation and avoid triggering spam filters, limit your daily sending volume per email to around 50 emails.

This conservative approach will help you avoid appearing like a spammer to ESPs.

Also, you can slowly ramp-up your daily sending limit from 3 to 50 to avoid alerting Email Service Providers (ESPs).

The best part of limiting your daily sending volume – ESPs see this as a responsible email-sending practice and help you build trust with them.

Guidelines Provided by Google, Outlook, and Other ESPs to Avoid Spam Filters

In 2024, I’ve seen the updates from ESPs like Google and Yahoo focusing more on safer, less spammy inboxes.

I’ll sum it up for you. 

You simply need to keep a watch on three things,

• Authenticate your email.
• Allow visible and easy unsubscription options.
• Ensure that you are sending an email that your recipient might look forward to. 

Also, very soon (probably in 2025), Google is expected to roll out a clear spam rate threshold, which will restrain senders from bombarding unwanted emails.

So, do keep an eye out for it to roll out. I will be sure to share details on that too (whenever Google announces it).

TL;DR – How to Avoid Spam Filters

I know it can be too much to process, but here’s a summary to avoid spam filters.

• Personalize your emails: Make sure you tailor emails to each recipient.
• Check Spam Scores: Use tools to assess email deliverability.
• Clean Your Email List: Ensure email addresses are valid and permission-based.
• Authenticate: Implement SPF, DKIM, and DMARC for better email authentication.
• Warm Up: Gradually increase email volume to build sender reputation.
• Comply with Guidelines: Adhere to regulations from Google, Outlook, and other ESPs.
• Monitor: Track email metrics, respect unsubscribers, and adjust strategies as needed.

FAQs

1. What happens if my emails still land in spam despite following best practices?

Even if you do your best, your emails might land in spam. To avoid this answer these questions to yourself, and you’ll know the answer,

1. Do you have a high email bounce rate? – This means that your email list is not clean.
2. Are emails unread and marked as spam? – It means that your subject line is either salesy or simply not interesting.
3. Are you warming up your email accounts?
4. Do you have enough sender accounts?
   See if your email accounts match the basic requirements. (Use this sheet to calculate the requirement)
   
   

2. How can I monitor my sender reputation?

Here’s a list of things you can do to monitor your sender reputation properly,

• Google Postmaster Tools: Check your domain’s reputation with Gmail users.
• Microsoft SNDS: Monitor how Microsoft views your IP.
• Third-party Tools: Use tools like MXToolbox, SenderScore, or GlockApps for overall reputation tracking.
• Feedback Loops (FBLs): Sign Up with ISPs to track spam complaints.
• Email Metrics: Watch your email platform’s bounce rates, open rates, and spam complaints.

3. What tools help me check email authentication (SPF, DKIM, DMARC)?

Here’s a list of tools that can help you check email authentication,

• MXToolbox
• DMARC Analyzer
• Google Postmaster Tools
• Mail Tester
• GlockApps
• DKIM Core
• SPF Record Check by Kitterman
• Postmark DKIM Validator