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How to avoid spam filters when sending emails?

11 min read
2112 reads

Professionals spend a lot of their time trying to understand how to avoid spam filters but at times they miss on a few common best practices which lead their emails in the spam filter.

We all know that spam filters are getting smarter and the ways to tackle them are getting tougher but don’t worry, we got that covered for you.

This blog would briefly explain to you the most important factors that you need to take care of, in order to prevent emails landing in the spam filter.

There is no reason to worry when you are real and have no spamming intention. 

Certain casualties need to be avoided, and care should be taken to avoid spam filters while running email marketing campaigns (sequences).

Let’s first try and understand what these filters and traps are.

What is spam and how to avoid spam filters?

Spam is any unsolicited email sent to a group of people. 

Each email service provider (ESP) wants the system to be free from such unsolicited emails, which is why they place an incoming email filtering algorithm and throw all these unwanted emails in the spam box.

This algorithm has evolved over these years, and they have included multiple triggers which could make your email look spammy to them.

To avoid spam filters and land in the inbox of your recipient, make sure that you go through these factors and follow as many as possible.

Different factors of spam emails

  1. Subscription related factors
  2. Technical factors
  3. Email template related factors
  4. Other factors

1. Subscription list related factors

  • Build your email list:

It is necessary that you build your own email list rather than renting them from a third party. 

This will ensure you that all the email addresses are genuine and you don’t end up sending to an invalid email address.

Organically building your email list may be time-consuming but in the long run, it will increase your email creditworthiness.

The better your email list, the lesser emails will get bounced and the higher are your chances of avoiding spam filters. 

Besides, consider cleaning the email list every once in a while to avoid any casualties.

  • Provide double opt-in

Double opt-in is the permission that you take in the form of verification mail sent to the recipient. 

This will ensure high engagement rates, and you will not end up in the promotions tab of the recipient’s inbox.

So, the next time any subscriber mistakenly gives you their email address, they don’t regret it and the ones who actually subscribe to it, are the cream layer of your recipients.

Set expectations when people join your list

“Make the wall before the storm” by clearly defining the engagement terms and setting a clear expectation, when the subscribers join.

Don’t send low-quality material to your subscribers in order to keep their expectations high. This will leave a lasting impression on their mind.

  • Include an unsubscribe link

Just like the consent while opt-in, you have to add an unsubscribe link. Users who are not interested in receiving your amazing emails are not worth wasting your capacity for.

You can easily add the unsubscribe link in your email campaigns (sequences) in the Saleshandy dashboard.

Spam filters are more aggressive than ever before and to avoid coming in their radar, it is important that you try to take precautionary actions. 

Even though your email is worth a read and a genuine one, there are chances that you might land up in the spam box.

Requesting the recipient to add you to their address list gives the spam filter an assurance that the address is genuine and they include you to their whitelist.

2. Technical factors

  • Monitor your email engagement metrics

Email engagement metrics like the open rate, reply rate will let you know that the content that you are sending is being read by the recipients.

A high engagement metric will work as a green flag to the spam filters. Always keep a track on what kind of content is liked by your subscribers and change content accordingly.

To monitor your email engagement metrics use Saleshandy. It will give you daily reports on how your email campaigns (sequences) are doing and help you see the trend of your users’ interests clearly.

Try to provide both HTML and a plain text.

Using HTML emails will increase the readability as they are visually appealing. But not all email users have a default setting in their inbox which renders the HTML template that you sent.

As a result, they won’t have a proper understanding of what you are trying to communicate and chances are high that they would mark your email as spam if they don’t have an easy way to view a non HTML (plain-text) version of your email or view the email in a browser window. 

This activity by a couple of your recipients will trigger the spam filter which would decrease deliverability of your future emails.

Hence, it is advisable to have a plain-text copy of your email even if you are sending an HTML version of the same.

  • Test your emails before sending them

There are tools that will tell you the spam score of your email. 

These tools work just like spam filters. Mail-Tester is one such tool. Send your email to the asked email address and check how likely you are to avoid spam filters.

Most importantly, never use a black-listed domain to send email campaigns(sequences) as it will reduce your domain reputation and result in undue attention to spam filters.

  • Set up DKIM and SPF records

For better email deliverability, it is essential that you authenticate your email address by setting up Sender Policy Framework (SPF) and DomainKeys Identified Mails (DKIM) records for your domain. This will result in higher email rates and avoid spam filters.

  • Have a low bounce rate

There are two types of bounce.

  • Hard bounce – When the email addresses in your email list don’t exist.
  • Soft bounce – When the inbox of the recipient is full.

Hard bounce will be a definitive reason why your email will be spammed, and it is important that you ensure that your bounce rate is not high.

Make sure you have verified your email list before sending it which will reduce your bounce rate. A bounce rate of 3-4% can be considered as normal, but beyond that, it needs to be alarming.

  • Try to personalize emails

Personalizing your emails increases the engagement rate by 22.2%. Using personal labels will attract the attention of your recipients, which will, in turn, increase the open rates and decrease your chances of being recognized as spam.

3. Email template related factors:

  • Limit the links in email

A lot of links in your email body paragraph may invite the attention of the spam filter. So try to limit the links and also ensure that the content in your mail matches correctly with the attached link.

Avoid CAPS, BOLD and exclamation points.


This is what a classic spammer would do in order to gain fast attention from lots of people. Choose the proper font and color for your text.

The format of the email should be standardized. An entire text with RED color is a big NO. Make sure that the text is written in line with the guidelines provided by the email services provider.

  • Stay free from spam trigger words.

There are a few words that are said to be triggering spam filters. You need to avoid these words from your email. It is tough not to use all these words but try and keep them as low as possible. Here is a list of all the spam filter trigger words.

  • Control image to text ratio.

Consider using fewer images in your email as it may seem filthy and the filer might take the content as spam. 

A low image to text ratio will ensure genuity. Also, consider keeping the images of the proper pixel and correctly displayed for more brownie points.

  • Avoid using video, flash, or javascript within your email.

Adding video to the email might tamper the alert signal of the spam filter. If it’s really important, then you can use an image and link video on that image. 

A javascript is not that highlighting factor that invokes the attention of the spam filter, but it needs to be checked while drafting your email.

  • Write brief and valuable content.

Don’t jam-pack your email with keywords and also consider that you write a brief email that is always welcoming to criticism and responses from the recipient.

Keep in mind that the recipient is not free to read the long paragraphs so keep the email resourceful and learn the Maxim “Less is the new more.

4. Other factors

  • Sending too many emails at one go.

It is smart to campaign (sequence) your emails but it is smarter to make sure you have enabled human-like sending.

Tools like Saleshandy randomize the time period between two emails in a way that spam filters would think that it is a human sending these emails individually.

  • Over-eager follow-ups(steps)

Follow-ups (steps) are super important while writing an email but at what cost?

Don’t keep on following up with a recipient who has already responded or is not interested in you.

There are high chances that the recipient will get irritated when you report your emails. In short, don’t irritate your recipients in order to avoid spam filters.

Regularly update yourself with the email sending laws and the ISP changes in spam filter technology.

Email sending laws have a few changes every month. Make sure you keep yourself updated with the laws and are not doing anything that is out of the legal boundaries.

Since you are not doing anything illegal, the spam filter has one less reason to verify you.

  • Stay away from adding forms to your email
  • To spam filters, adding forms in your email copy is a red signal. Forms provide a security risk and are not supported by many email clients.

    You can link to the page you want them to visit instead of adding forms in the email body.

    • Stay away from attaching files

    Spam is generally sent in a form of an attachment in order to spread viruses amongst computers once it is downloaded, and there is no telling whether removing malware will be easy if you open an email with a corrupted attachment.

    This is the reason spam filters take extra care of attachments.

    Don’t attach a file to your email and if you have to, then use secure document links.


    In short, the algorithm of these spam filters is evolving with each passing day. They are trying to remove the slightest possibility for a phishing or spam email to reach the inbox.

    To ensure that all your content is delivered without being trashed, you need to be sure from all the sides.

    Use these factors for yourself and you’ll see positive results.

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