6 Ways to Reduce SpamAssassin Score to Avoid Spam Folder

Did you know that nearly 45% of emails sent in 2021 were spam? Spam emails are everywhere, but inboxes have become adept at filtering them. We should give some credit to various anti-spam solutions that have emerged over the years. One of them is SpamAssassin. SpamAssassin is a tool widely used by administrators and ISPs to detect spam.

Curious about how SpamAssassin works, how scores are calculated, and how to maintain a good score? Keep reading to find out!

What is SpamAssassin?

SpamAssassin is a widely used open-source software developed by the Apache Foundation. It uses complex algorithms and analytical tools to scan and analyze emails, determining whether they are spam or not based on various criteria, including content, sender reputation, and more.

SpamAssassin can be directly integrated with a mail server to automatically filter out spam emails. Many ISPs may also use it as part of their spam filtering process to filter and classify emails as spam and block them from getting sent to people's inboxes.

SpamAssassin uses powerful scoring frameworks and plug-ins to integrate advanced heuristic and statistical analysis to test the following email components to identify spam emails:

• Sending IP

• Subject line

• Email headers

• Email authentication

• Content and formatting of the email

• Message encoding

Apart from checking components of the email, it uses multiple techniques and checks to identify if the email is spam, like Bayesian filtering, blacklist checks, etc.

After completing all the tests, it calculates a score for each email and determines whether it is spam.

What is the SpamAssassin score?

The SpamAssassin score is the rank that indicates the possibility of an email being spam. A higher score means it's more likely that the email is spam, whereas a lower score suggests that it’s not.

SpamAssassin assesses each email attribute and then assigns an overall score. Positive scores usually indicate probable spam, while negative ones indicate that it is unlikely to be spam.

SpamAssassin's default score for an email to be considered spam is "5" and above, with a maximum score of "10". However, system admins and ISPs sometimes adjust this score to be lower or higher than 5. As thresholds vary, it’s essential not to rely solely on the default score but to aim for the lowest possible spam score to improve email deliverability across different systems.

6 ways to keep your SpamAssassin score low

SpamAssassin experts say that as long as your email is not spam, you don't have to worry too much about hitting rules within SpamAssassin, and even if you do hit one, it wouldn't be a high enough score to be a problem.

So, if you are a legitimate sender, but your SpamAssassin score is higher than you'd prefer, here are a few best practices you can follow to reduce your score and your likelihood of being mistaken for spam.

1. Show your legitimacy as a sender

As a legitimate sender, you don't have any reason to hide your sender's information like "from" and "reply-to". So, provide correct and accurate sender information and also ensure that your domain has a verifiable IP address that people can look up to confirm your identity.

Your legitimacy is also shown through your sender reputation, and with every email you send, you build the sending history for your domain and IP address.

As long as recipients open and interact with your emails, you will have a positive reputation. But if your emails are noted as spam by readers or even ignored, then it will harm your sender reputation.

2. Avoid mistakes in the code of your email

Mistakes in HTML codes can be unbalanced tags, invalid tags, default titles, etc., and it can lead to your email being misinterpreted as spam. So, you should double-check to avoid any mistakes or missing components in the HTML.

Also, when composing HTML emails, ensure a fallback version or text section for people who don't want to see the HTML version.

3. Set up email authentication

Email authentication protocols help maintain email security by assisting email servers in identifying legitimate senders from scammers pretending to be reputable brands.

SpamAssassin checks for SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) when it scores an email, and even if you miss one, your score will be affected. So it's best to set up email authentication to lower your SpamAssassin score.

DMARC might be a popular authentication method that gives you more security, but it doesn't directly impact the score. We would still recommend you implement it to be on the safe side.

4. Avoid using too many images in your emails

Using an image or two in your email will not be harmful, but avoid relying heavily on it to deliver your message, as image-only emails don’t give SpamAssassin a good impression. While it may not drastically increase your score, it's something you must keep in mind if you want to reduce your score.

We would recommend you keep the number of images in your email below 40% of the total message size and always write alt text for the images. Alt texts ensure that the email makes sense even if the images fail to load or emails are viewed in text format.

5. Be careful when adding links to your email

There are chances that the domain you have linked to in your email can be on a blocklist and have a poor sender reputation. If you link to those sites in your emails, you might be labeled as an 'accomplice' and it might influence your reputation.

In fact, even some promising, genuine companies can have a bad sender reputation, and it is hard for you to know that. So be wary of linking other sites in your emails.

6. Be consistent with your email sending frequency

Begin by gradually increasing your email sending volume and maintaining a steady pace over time. This helps establish trust with spam filters, as consistent activity signals reliability. Sudden surges in email activity often resemble spam-like behavior and may trigger filters to flag your messages. By warming up your domain and showing a history of legitimate and consistent emailing, you demonstrate credibility, reducing the likelihood of your emails being marked as spam.

Wrap up

SpamAssassin is an essential tool for assessing the quality of your emails and ensuring they pass through spam filters effectively. While following the tips mentioned won’t guarantee immunity from being flagged as spam, they significantly improve your chances of achieving a low SpamAssassin score. By adhering to best practices like authenticating emails, writing engaging content, and maintaining a consistent sending pattern, you enhance your email deliverability. Focus on building trust with spam filters, and your emails will be more likely to reach your audience's inbox.