Maximizing Email Deliverability and Avoiding Email Spam Filters

Don Vizcaino Headshot Image

Don Vizcaino

Executive Director of Global Strategy

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Russell Trzaska Headshot Image

Russell Trzaska

Enterprise Success Manager

Don and Russell have more than a decade of experience in the email marketing and data space.

At Zerobounce, Russell and Don helps thousands of companies improve deliverability, protect their sender reputation, and keep their email marketing at the top of its game.

An email that doesn’t end up in the inbox of a target recipient is a waste.

It’s so important to maintain your ability to deliver outbound emails successfully. In the past, it was easy to warm up a cold email campaign and maintain good email deliverability at scale with a few simple best practices.

However, modern spam filters now use advanced algorithms and artificial intelligence to remove spam quickly by analyzing billions of emails in real-time. More than ever, cold emails are being removed before ever reaching a prospect’s inbox.

At the same time, recipients still have to filter their inbox anyway throughout the week because of the volume of emails they receive every day. Most recipients are skilled at spotting spam and ignoring irrelevant emails that end up in their inbox.

This level of sophistication has made it harder than ever to ramp up and sustain a cold email campaign. Marketers need best practices to combat these recent changes in email deliverability.

Filtering Spam Email: Before You Start

Today’s Internet Service Providers (ISPs) are very sophisticated.

The job of ISPs is to protect consumers, so they’ve done a retrospective analysis of billions of past emails to identify the common traits of spam.

Modern spam filters leverage these triggers to scrutinize email content, tendencies, and recipient behaviors in real-time.

ISPs review millions of emails every day and share information regularly to spot inboxes that are potentially harmful to their community.

It only takes a few triggers to get filtered as spam or flagged for further scrutiny.

To build a successful cold email system in this environment, you have to be proactive about your email deliverability and have the right best practices to save you trouble down the road.

Email Health & Deliverability

Not all emails and email servers are the same.

Employees leave. Companies change their email address format. Most email servers are setup to accept all email formats (even invalid ones).

To ensure optimal deliverability for your campaign, you need to be able to determine the health and validity of your emails.

You likely know about invalid emails, which are old, fake, or improperly formatted emails that cause the email server to autorespond with a bounce message.

However, invalid emails aren’t the only issue to worry about for your list.

A Spam trap is an email address created by ISPs and blacklists to attract and detect spammers. These traps are invisible until you look, so ignoring them can damage your deliverability.

Finally, you should avoid email recipients that are known to submit abuse/spam reports. Not only does their lack of engagement decrease performance, but it also impacts your ability to deliver emails.

It doesn’t take many bounced emails, spam traps, or abuse reports to damage cold email deliverability. To protect your email delivery, you should regularly verify your lists using a validation solution like Zerobounce.

Sender Reputation & Email Delivery

The health of your email list isn’t the only factor to deliverability. Just as important is your reputation as a sender in the eyes of Email Service Providers (ESPs) and ISPs.

ISPs use your behaviors and how recipients react to your messages to determine whether or not you’re a risky inbox to their community.

Even if you keep the list clean with valid emails, recipients who repeatedly don’t interact with your messages will diminish your sender reputation over time because it indicates potentially spammy emails.

To maximize your sender reputation and avoid spam filters, you should refine your list over time to the people who have interacted with your brand or email content. Regularly review your audience to find those that are disengaged, unqualified, or unproductive.

Tips to Avoid Email Spam Filters

Avoid Triggers From Email Content

The content of your email is scrutinized heavily. ISPs look for specific keywords, measure the ratio between text and HTML, and compare your emails to find patterns in your messaging.

Since ISPs track the differences between spammy and regular email communications, they use this information to see which one compares best to your email content.

Many marketers include content in their email that seems normal, but it actually hurts your sender reputation or causes spam filters to treat your emails differently.

For example, a common trigger for spam filters is including a picture with a link. Other examples include colored text, too much capitalization, exclamation points, or too much HTML.

Configure Your Server Correctly

Your domain, IP address, and ESP are all involved in sending emails. Today, communicating with other email servers requires proper authentication and following security protocols.

At a basic level, you need to setup a few key items to ensure proper deliverability:

     1 – Connect Your Domain & ESP: Add MX, Cname, and TXT records to your domain settings to give an ESP like Gmail or Outlook permission to send emails on your domain’s behalf.

     2 – Setup a SPF Record: A Sender Policy Framework (SPF) helps authenticate your emails and prevent spoofing by identifying which authorized IP addresses can send on your behalf.

     3 – Setup a DKIM Record: DomainKeys Identified Mail (DKIM) helps further validate your email messages and protects from abusers by adding digital signatures to verify your emails.

     4 – Setup a DMARC Record: Domain-based Message Authentication, Reporting, and Conformance (DMARC) is an additional layer of protection. DMARC works together with your SPF and DKIM to protect from abuse by verifying the origins of your email messages.

Online deliverability tools like GlockApps or MX toolbox give you in-depth diagnostics on your server configuration so you can improve setup, troubleshoot, or fix issues.

Differentiate Your Email Content

Templated emails sent to the same prospects is a clear sign to spam filters that an email account is sending potential spam.

ISPs know how people engage in normal email communications. One behavior these types of people wouldn’t do is blast out repetitive, impersonal content to a large group of recipients.

To get past spam filters, you should differentiate your emails by personalizing your messaging. Not only does this help maintain your deliverability so you can follow up, it also increases the chance you capture attention.

Just Getting Started with Cold Email? Here’s Don & Russell's Advice:

Understand There’s a Learning Curve

New cold email marketers tend to view cold email as a magic bullet: send emails and make money based on your volume.

Unfortunately, that’s not always how sales processes happen with outbound.

Understand that there is a learning curve to cold email. It’s unlikely your campaign will immediately generate outbound sales without the right research and testing.

Data is Powerful

In this era of marketing overload, buyers deal with hundreds of outbound messages every day and know a majority of them are automated.

Rather than spend the time manually reviewing these messages, recipients often ignore outreach unless it appears unique, human, and personalized to them.

If you can speak directly to the customer, you’ll increase your chances of resonating with prospects while also avoiding messaging that can end you in spam. Collect as much information as you can on potential customers to help improve your messaging. 

Provide Value First

It usually takes a lot of sales touches to connect with a prospect in today’s sales environment, so you need to think long-term about how you want to engage with them over your cold email journey.

Your first email should be an intro email and you shouldn’t be asking for anything. Instead, focus on differentiating yourself and sharing something of value.

People often won’t budge until you’ve provided value to them first. Provide as much value as you can before asking for something in return.

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