By Nayana Somaratna
Last updated: April 16th, 2020
If you’re reading this, then you probably have some experience with email deliverability in your day-to-day work. In fact, there’s a good chance that you have a sound list of dos and don’ts in place already.
We’d like to share with you our own 44 point checklist, which we’ve put together after years of experience with this stuff. Our checklist is comprehensive and may likely overlap with many of your own best practices. However, we believe that you’ll find here fresh new insights (including all our reasoning behind each point) - knowledge you can truly capitalize on.
With that said, let’s jump into our pro’s checklist!
Since 44 points may seem like a lot, we’ll start with organizing them into clear email component categories:
These categories have no particular order and can be scrutinized independently. At the end of our article, we’ll provide you with a checklist summarizing the items explored.
OK, let’s dig deeper into each category’s suggested action items and the rationale behind them.
Make sure all your subscribers have consented to receiving your emails. If more than a few subscribers manually mark your emails as spam, their email service provider will assume you’re sending spam.
Avoid sending emails to invalid or non-existent email addresses. If too many of your emails bounce, email service providers may assume you’re sending emails indiscriminately.
If a subscriber has not opened any of your emails for 3 months or more, remove the subscriber from your subscribers list. The lower the percentage of subscribers who open your emails, the higher the likelihood their email service provider will assume that you’re sending spam. Also, certain email addresses can become “spam traps”: a practice where email service providers keep open email accounts already closed by users in order to trap would-be spammers. Emailing such an address is a guarantee that you’ll be marked as a spammer.
Ensure that these technical parameters have been set up properly. Most email delivery services (e.g., SendGrid, Mailgun, etc.) do this automatically for you. If SPF and DKIM haven’t been implemented, your emails will most likely end up in the spam folder. DMARC and reverse DNS are less important, but should be set up if possible.
Send emails from your own domain (e.g., monsoonyeti.com). Avoid using a public service (e.g., gmail.com, etc.). Using a custom domain increases your credibility. This also allows you to control your sender reputation.
Avoid special characters in your custom domain names, especially homographs. Many phishing emails use special characters to fool readers (such as typing something that seems legitimate, ɢoogle.com; but with a unicode character that isn’t authentic, ɢ). Using similar characters in your domain name increases the likelihood of your emails being marked as spam.
If you’re using an email delivery service that supports dedicated IP addresses, or if you are running your own dedicated email infrastructure, make sure to use the same IP address all the time. Sender reputation is specific to a given sender email address and IP address. For more details, please read the item Check sender reputation of email domain.
When sending different types of messages (e.g., promotional messages, customer support messages, etc.) use a different sender email address (e.g., email@example.com, firstname.lastname@example.org). If possible, use a separate dedicated IP address for each message type as well. Different types of messages will have different open rates. For example, transactional emails (e.g., confirm email address, reset password, etc.) have higher open rates than marketing emails. Separating message types ensures that crucial transactional emails are less likely to end up in spam. Please also see the item Avoid having multiple message types in the same email.
Email service providers are very careful with new sender email addresses and dedicated IP addresses. If you start sending large volumes of email at once, you may be flagged as a spammer.
Before sending your emails to your entire list of subscribers, send them to a small number of real email addresses. This helps detect deliverability issues prior to committing yourself and wasting valuable opportunities resulting from a positive first impression with subscribers.
Check if your domain name is already blacklisted or marked as unsafe or insecure. If you’re using your own email sending infrastructure, do the same for any dedicated IP addresses you have. If any of these have been marked as unsafe or blacklisted, your emails will end up in spam. In such a scenario, you may wish to consider obtaining a new domain name or IP address.
Conventional wisdom recommends that you check your “sender reputation” to see if your domain or IP address has a low reputation. The lower the reputation, the more likely your emails are to end up in spam. Your sender reputation is a score calculated by email service providers. Based on your score, email service providers classify you as either a good, neutral, or bad sender. The worse your reputation is, the more likely it is that your emails will end up in spam.
The reputation of a sender and the algorithms used to calculate the sender’s scores are unique to each email service provider, and are well-kept secrets. There’s no way for you (or anyone else, really) to know what your actual sender reputation might be. Nevertheless, several 3rd parties attempt to guess your “sender reputation” using their own proprietary algorithms. In our company, we don’t use any algorithms (proprietary or from a 3rd party). But since the use of algorithms is common industry practice, we’ve included the item in our checklist.
If you’re sending a large number of emails, make use of the “feedback loops” offered by the major email service providers. If you’re emailing Gmail or G-Suite addresses, use Google’s Postmaster Tools. Feedback loops will help you identify which emails or campaigns are going into spam.
Divide your subscribers into “segments” based on their profiles and interests (e.g., customers, partners, etc.). Customizing your emails by segment leads to better open rates and a lower risk of subscribers manually tagging your emails as spam. Over time, this will result in lower automated spam rates for you as well.
Send only appropriate messages to each subscriber segment. Sending only appropriate messages to each separate segment will lead to better open rates and a lower risk of subscribers manually tagging your emails as spam. Over time, this too will result in lower automated spam rates for you as well.
At a minimum, personalize each email by including the subscriber’s name. The more personalized and customized the emails you send, the better. Including the subscriber’s name in the email subject or body signifies that you know who they are. This reduces the likelihood of your email being spammed.
Certain tools (e.g., customer relationship management software, mailing list software, etc.) embed a tracking pixel in your emails. Tracking pixels are tiny images that are loaded from a URL when a user opens that email. A unique tracking pixel is generated for each subscriber, therefore allowing senders to track if and when the emails sent are opened. If you’re using several such tools at once, your emails may contain multiple tracking pixels. The higher the number of tracking pixels, the greater the chance that your emails will be marked as spam.
Ensure that all images are embedded into the emails themselves. Avoid images that are loaded from a URL. This is because external images can be used to track email opens, similar to tracking pixels. Therefore, email service providers treat them similarly, and may mark your emails as spam.
Avoid using links that have been run through a link shortener (e.g., t.co, bit.ly, tinyurl.com, etc.). Short links obfuscate the destination domain, so they’re often used in phishing attempts. Using them may lead email service providers to mark your emails as spam.
Certain words and phrases are common in spam and phishing emails. Avoid using them if possible.
If your emails have an HTML body, make sure the HTML is properly formed. Most email composition interfaces (e.g., Gmail’s send new email popup) do this for you automatically. Email service providers may mark emails with malformed HTML as spam, due to the following reasons:
Avoid using HTML/CSS tricks to hide content. Many phishing emails use this tactic to hide links and dangerous content. If you do so, your emails may also end up in the spam folder.
Minimize the use of multiple colors. Avoid using all caps (e.g., “HELLO, HOW ARE YOU?”) or similar non-standard writing styles. Many spam emails have unusual text formatting and unnatural writing styles. These enhancements simply increase the risk of email service providers sending your emails to spam.
Conventional wisdom suggests that emails that are mostly composed of images are more likely be sent to spam. Our team is currently testing this hypothesis. So, for now, we’ve decided to keep it in the checklist until we have enough data to argue otherwise.
If your emails have important images, make sure to add specific ALT text that will be displayed should recipients disable disable image loading. Certain subscribers (especially if they’re tech-savvy) will disable the display of images inside emails. Including ALT text ensures that the emails are readable nonetheless. Email service providers may consider the lack of ALT text another reason your emails must go into spam.
Keep your emails short and to the point. Short and focused emails have better delivery rates.
Avoid multiple communication objectives in a same email (e.g., do not add a product promotion message to a confirm your email address email). Including multiple objectives in a same email increases the likelihood that it will end up in spam.
If your emails have a signature, make sure the name of the sender and name in the signature match. Email service providers may consider a mismatch to indicate that your email is spam or a phishing attempt.
Ask your subscribers to manually move your emails from the spam folder to the inbox. Just as subscribers manually spamming your emails is a strong signal to email service providers that you are sending spam, their doing the opposite is a strong signal that you are not sending spam. The more users that do this, the better for you.
Just the same, ask your subscribers to add your sender email address or addresses to their contacts list. Emails coming from email addresses in a recipient’s contact list are less likely to end up in spam.
Make sure that your emails have an unsubscribe link. Most email delivery services (e.g., SendGrid, Mailgun, etc.) do this automatically for you. If you don’t provide an unsubscribe link, email service providers are more likely to mark your email as spam. Moreover, if you don’t provide a clear unsubscribe option, users who do not wish to continue receiving your emails will be forced to manually spam your emails. This may severely impact your deliverability.
Just the same, include a one-click unsubscribe option in your emails. Many email delivery services (e.g., SendGrid, Mailgun, etc.) do this automatically for you. If your email has a one-click unsubscribe option, if a subscriber decides to mark your email as spam, the email service provider will display them a popup asking if they wish to unsubscribe instead. This will help avoid the deleterious effect of your emails being manually spammed.
Please also see the item Double opt-in all new subscribers.
Now that we’ve gone over all 44 points in our checklist, here you have them for your personal use:
As to us, we’re Monsoon Yeti, an education based marketing team to help you engage audiences better. For this specific topic of email deliverability, we offer our own email vetting tool, which allows you to safely determine whether an email subject line and body you’re about to send will be marked as spam by your audiences’ email service providers (i.e., "Inbox Placement").
Vetter is one of several other tools we offer at Monsoon Yeti, all related to education based marketing. If you require additional information or support, reach out to us at: email@example.com