Sender Reputation: How to Avoid Spam Folder Placement

Sender Reputation: How to Avoid Spam Folder Placement

Businesses and companies don’t always give priority to their email marketing programs focusing on developing new products, setting up goals and planning the strategies. They often start optimizing the email programs when their open rates drop in times. But the success of the business is closely connected with the success of the email program. The more messages go to the user’s Inbox, the more revenue the company gets.

The key to every email program is deliverability. Many companies are struggling with poor deliverability while losing revenue opportunities.

Your email deliverability is the key thing you should focus on in order to reach the user, engage them and grow your business.

What is Email Deliverability?

Some email senders assume that email deliverability is the percentage of email messages that didn’t bounce. It’s not.

Email deliverability is the percentage of email messages sent to the recipient’s Inbox.

When a message is put in the user’s spam, junk, or bulk email folder or is blocked by a mailbox provider, it’s not considered successfully delivered.

Consider this quick example:

You sent a message 100,000 email subscribers, 2,000 bounced (2%), 60,000 emails (60%) went to the spam/junk folder and 38,000 emails (38%) reached the Inbox.

Your deliverability would be 38%. 60% of your subscribers would potentially miss your email and you would miss the revenue opportunities.

GlockApps Spam Test: Inbox Rate vs. Spam Rate
GlockApps Spam Test: Inbox Rate vs. Spam Rate

The worst thing is that it does not only affect marketing emails. Account confirmations, password resets, purchase invoices, order confirmations and other types of transaction emails suffer as well. You are not only losing revenue but also you’re losing the subscriber’s trust.

Thus, monitoring your email deliverability and optimizing your email program for better deliverability is the must-have for every sender.

What Affects Email Deliverability

There is a set of factors that affect your deliverability. Of course, you need to keep both eyes on each of them, constantly monitor and improve them as much as possible.
Factors that impact deliverability:

  • sender’s reputation;
  • email authentication;
  • email infrastructure.

To have good email deliverability you should apply a complex approach. If even one of these factors has negative tendencies, there is a big chance your email will be filtered by the recipient’s server.

Sender Reputation: Be a Good Sender

Sender’s reputation is a good or bad position of the email address you are sending your letters from. Being a good sender means having proper emailing habits.

There are certain factors that affect your reputation as a sender: email engagement, the volume of sent emails, bounces, complaints level spam and blacklisting.

Email Authentication

Email authentication is a technical part of your email deliverability. It is a toolbox that is used to prove the authenticity of your email.

Tools of email authentication are:

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

All together these tools provide maximum security for your email: indicate if your email is really sent from one of your IPs (SPF), make sure that in the process of sending your email wasn’t changed by anyone else (DKIM) and also provide options of actions towards emails that didn’t pass first two steps of authentication (DMARC).

Nowadays implementing all three of them is a must for every brand that uses email marketing.

Email Infrastructure

Email infrastructure is another technical side that affects your email deliverability. It relates to your domain and IPs.

The important aspect of email infrastructure is basically where you start sending your emails from. Whether you have a shared IP or a dedicated IP. Weigh the pros and cons of using either of them and decide which one will work better for you.

Usually, if a mailer sends small amounts of letters, it is recommended to use shared IP. If the company is big, use dedicated IP, or even several dedicated IPs, segmenting them on the basis of email purpose (marketing, transactional, etc.).

Just like your IP, the domain you’re sending emails from has its reputation. Obviously, it should be monitored, because if the reputation is low, there is a big chance that your emails won’t reach the recipient’s inbox.

How to Improve Email Deliverability

The first step to fixing your email deliverability is checking your sending infrastructure and email authentication.

If the technical part of your email sending program is good, it’s time to assess your sender reputation.

Mailbox providers take the filtering decisions based on your sender reputation. Senders with a good reputation get their emails delivered, and senders with low reputation either get their emails filtered to the junk folder or blocked at the gateway.

Mailbox providers use a variety of factors to calculate your sender reputation, including:

  • recipient engagement,
  • email lists,
  • email content.

Recipient Engagement

There are different ways that the recipients interact with your messages: opens, clicks, unsubscribes, spam markings. These actions can be tracked and evaluated by email senders. In addition to that, mailbox providers may track other signals of positive and negative engagement such as:

  • how often messages are marked as not spam
  • how often messages are moved from one folder to another
  • how often messages are replied
  • how often messages are forwarded
  • how often messages are deleted without being opened
  • how often a sender is added to an address book

Spam complaints do the worst impact on the sender reputation. In the industry, a spam complaint rate above 0.2% is considered high and may result in poor deliverability.

Particular mailbox providers may have a lower threshold for a complaint rate. At Gmail, for example, a spam rate as low as 0.08% can start to affect email deliverability, which is why you need to watch it. Many mailbox providers have a feedback loop program that allows you to receive email notifications when someone reports your message as spam.

In 2018 Yahoo, AOL, and Verizon were merged into Oath Inc. which was renamed Verizon Media Group in 2019. What it means for the senders is that the data affecting sender reputation, such as spam complaints, at one domain can negatively impact sender reputation at all related domains. Though these domains may treat this data differently, it is wise to consider your email engagement data across these domains as related.

Although recipient engagement is measured based on different sets of data, the conclusion is:

Send emails to valid subscribers who want to receive them, and you will build a good sender reputation and will most likely have high, sustained deliverability.

Valid Email Adresses List

When speaking about email lists, you should keep a close eye on invalid email addresses and spam trap addresses.

Repetitive sending of emails to a large number of invalid email addresses is a negative signal to mailbox providers. You have to suppress hard bounce email addresses from your mailing lists after the first bounce.

With the GlockApps Bounce Tracker, you can get in-depth bounce email analytics including the break down by the sender email address/domain, bounce type, bounce reason, and mailbox provider and you can detect peaks of your bounce emails over time.

It is a good way to understand which mailbox providers block or drop your messages or which senders or campaigns generate high complaint rates.

GlockApps: Bounce Email Analytics
GlockApps: Bounce Email Analytics

It is also a good habit to determine and suppress inactive email recipients. If a user has not opened any of your emails for 3 months, it is likely an abandoned email account which should not be emailed to.

What is a Spam Trap?

Spam traps are email addresses that should never receive any emails.

A recycled spam trap is an abandoned email address that was turned into a trap by a mailbox provider after a period of non-usage by the owner.

A pristine spam trap is an email address set up by an anti-spam organization or mailbox provider with the only purpose to catch spammers. Such email addresses never sign up for any mailing lists and must not receive any emails.

What You Need to Know about Spam Traps

Read this 12-page whitepaper to learn about deliverability issues caused by spam traps
and what to do if you are already blocked.

 Download PDF

Sending to spam traps means that you aren’t collecting your list properly or aren’t keeping your list clean.

How to Avoid Spam Traps

You can avoid spam traps by growing your email list organically using a confirmed opt-in process and by removing email recipients from your list after long periods of inactivity.

A confirmed opt-in method will also protect you from human typos and malicious submissions. By clicking the link in the confirmation email the user confirms that they gave you the right email address for contact and that they want to receive your messages.

We can’t stress enough how dangerous and harmful for your sender reputation and deliverability purchased, rented or scraped email lists can be. Avoid them by any means.

Email Content

Content is not just the words in your message. The email template, links, images, subject lines, footers, and signatures – all of them impact email deliverability.

To build a good sender reputation, you need to send a message that meets the expectations of your subscribers, has a professional look and feel, and contains legitimate links.

Avoid using too many images in the content. The best choice is 65% of text and 35% of images. Consider putting the images on your web server and link to them from the message to decrease the message size and increase the load speed.

Links often stay overlooked because they don’t seem to be very important. However, links you use in the message can make a big difference where the message lands.

Use the links only on legitimate and trustworthy domains. Many senders like to convert long links using link shorteners tools. This could be a red flag for spam filters as they used to see shortened links in spam emails. Spammers often use link shorteners to mask links to phishing and other malicious pages.

Blacklisted domains in links might add to the email spam score and affect email placement as well.

You can start investigating your email deliverability issues by testing different things in the email content. Change the Subject line, the message format, remove links, images, re-write the copy and test after each change. There is a good chance that your deliverability will improve at some point. If it doesn’t, then dig deeper and test different sending email addresses, domains and IP.

Here there is a good guide on how to find out why the email goes to the spam folder.

Email deliverability is never guaranteed. But you can drastically increase the chances of being delivered if you watch what you are sending and how your recipients interact with your emails.

If you are curious about how mailbox providers treat you as a sender and where they place your messages, you might test your email placement with GlockApps.

GlockApps Spam Testing for Marketers and Agencies

GlockApps Spam Testing

Test your email placement

Scan your emails through all the major spam filters before you send them.

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Get actionable tips for improving the delivery rate of every email you send.

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Improve your overall email performance by delivering more emails to the inbox.



Julia Gulevich is an email marketing expert and customer support professional at GlockSoft LLC with more than 15 years of experience. Author of numerous blog posts, publications, and articles about email marketing and deliverability.