Avoiding the SPAM Folder and Deliverability Best Practices

Kate Reinarz, Jr. Marketing Manager

Kate Reinarz, Jr. Marketing Manager About The Author

July 24, 2019


Deliverability in digital marketing is key - by this we mean taking steps to help your email reach the inbox of your recipient. Since each email server uses its own criteria and process, it can be tricky to pinpoint exactly why an email went to SPAM. However, there are plenty of things you can do as a digital marketer to ensure the best deliverability possible.

Here's a quick checklist of email content do's and don't's:

01. Don't use bought lists.
Unless, that is, you want to ruin your reputation as a sender. These lists will very often contain undeliverable email addresses that will tell email providers you're sending unsolicited messages, almost guaranteeing you a spot on the spam list. These are called "spam traps". The list of reasons to avoid bought lists could go on, but the point is simple. Don't. Buy. Lists.

02. Don't make the body of your email one giant image.
Spam filters can't read images - so to them, this is unidentifiable content. If you want to include an image, you should legitimize it using something spam filters can read, like text. A good rule of thumb? Try to include at least two lines of text for every one image your email contains.
Additionally, pay attention to how many images you have and how large they are. The best advice is to ensure that each image is under 1 MB in filesize. If you’re not sure how big your images are, a good practice to be in is to scale your images down to roughly 600-800 px wide. Nowadays it’s pretty common for images to be very large, but in an email environment an 800 px wide image will look great!

03. Avoid "spammy" language - especially in the subject line.
"GET RICH NOW!!!!!", "BEST DEAL EVER!!!!!", "~!&* ACT NOW FOR AN EXCLUSIVE OFFER *&$!~"...Don't even think about it.

04. Always provide the option to unsubscribe.
To be compliant with CAN-SPAM laws, you must have a link in your email where a recipient can choose to unsubscribe from you. For example, in rezora, this is built into the footer of each template. Double check to make sure all the emails you're sending have an easily accessible "Unsubscribe" link.

05. Avoid embedding videos.
Most email clients do not support videos, which is likely to land your email in the spam folder if it contains a video. A great workaround is to include a screenshot of your video that is link to the video when clicked. See here.

06. Pay attention to your links.
Make sure they're legitimate, and make sure they work by clicking on each of the links before you send the email!

07. Get yourself whitelisted.
If you're going to send a marketing email to a large group of recipients, you should be using an established email marketing service (as opposed to sending directly from your own email server). Furthermore, it's a great practice to ask your contacts to add your email address to their address book - which should allow you to easily pass into their inbox without getting stopped up by spam filters!

08. Analyze engagement.
Many email tools provide you with analytics on your sent emails and your contact engagement. Don't send to stale contacts. If you see a contact hasn't clicked on a single email you've sent them within, let's say, 6 months - delete them from the list you're sending to and move on. Alternatively, craft an unsubscribe email that could potentially bring them back - here are some great examples.

09. Don't copy and paste large amounts of text/images.
When you do this, characters that aren't readable by web clients are created wherever you paste the content, and this raises a red flag to spam filters.

10. Don't be a stranger.
Bottom line? Make sure you know who you're sending to. And more importantly, make sure they know who you are. Send a welcome email when you obtain their email address!

But what about email server compliance best practices? When you send a contact an email, their email server performs quite a few "checks", and makes the decision on how to receive that email. It's important to know that it's not always a simple pass/fail - I'm sure we've all seen some examples of this one before. For example, an email might go to the inbox, but with some content blocked (requiring permission to download images, etc.). An email might be diverted to SPAM, or refused completely (this is called a bounce).


One of the 'checks' that receiving email servers perform will be to authenticate your email - is the sender who they say they are? This is done primarily to avoid phishing and spoofing, which is when a sender purposely misrepresents their identity. Phishing is very often done to attempt to smuggle-in malicious content or code.

Did the sending IP Address have permission to send on behalf of that domain? The email server of each of your recipients will check with the from address’ domain, and check to see if rezora has permission to email on its behalf. The best way to ensure that this authentication is successful is to use your company-provided email address specifically. This is really important! Your company email address has good settings in place to ensure that your emails are properly authenticated, and you’ll see the best results using that address.


One of the most overlooked factors is your contacts themselves! Contact management and sending practices are a big factor in your personal reputation online, and each contact may have individual settings in place affecting how emails are delivered to them.

Are your contacts expecting your emails? This may sound like an odd question, but it’s really important! Did each of your contacts signup to receive your emails? With GDPR now in effect, it’s more important than ever to make sure that you have a record of when that contact signed up for your emails, but it can also be a factor in deliverability! 


One of the most important factors in digital marketing is reputation. The receiving email server will check the online reputation of the ‘From’ email address (e.g. agent@companywebsite. com), the address’ domain (e.g. companywebsite.com), and the sending IP address (rezora’s). The internet community keeps track anytime someone marks an email as SPAM, or if a particular domain or IP address have lots of bounces, and will influence how future emails are delivered as a result.

What if the online reputation of the ‘From’ domain -- is it known for sending SPAM? As you send emails on behalf of your company domain, the online community will “keep track” of the results. Fewer bounces lead to better and better results, and more bounces or reports of spam can have adverse effects.

What if the online reputation of the sending IP Address (rezora’s) - is it known for sending SPAM? Here at rezora, we go to great lengths to protect the online reputation of our sending IP addresses. Our developers monitor for issues, and quickly take action if we spot anything amiss. We maintain a bounce list to prevent unchecked repeat bounces, and help our users increase deliverability through our support team.

What if the online reputation of that ‘From’ Address - is it know for sending SPAM? The internet will remember your sending practices too! As you send marketing pieces, do everything you can to prevent it from going to SPAM, and your email address will become known in the community as ‘reputable’.

Happy sending!


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