Often we as marketers are so focused on email artwork, UX and UI that we neglect looking at the metrics of our perfectly crafted emails. Problem is, you may have designed the BEST.EMAIL.EVER. but nobody may have even seen it (think tree falling in the woods analogy…). That being said, now more than ever, deliverability metrics need a closer look and here are a few checkpoints to get you going.

Issue 1

Spammy Subject Lines 

The Culprit

Internet Service Providers (ISP) are cracking down on what they suspect are “spammy” subject lines, which is keeping you away from the customer’s inbox. Constantly using ALL CAPS in subject lines will increase the probability of this occurring, as well as using words such as “Flash Sale” or “Blowout” or “Free” …or even worse, a combination of both (FLASH SALE, FREE, DEAL and so on). Using symbols such as asterisk (*) in subject lines are also not a best practice, since this often implies a slew of terms and conditions associated with what was just written. Bottom line, ISPs are just trying to protect customers from spam or fraudulent email senders, so if you look like those companies who offer a  “FREE Trip to Bali…Open to Enter*” then chances are you’ll end up in a spam trap.


Replace “spammy” words in subject lines for less trigger inducing ones (see below) or use intriguing/mysterious content which will want to make a customer open the email. You can also include sale/deal information in the Pre-Header of the email as a continuation to the Subject Line. Furthermore, if using Salesforce, benefit from the Return Path extension and test subject lines in the Inbox Preview Tool before sending to your entire database. Finally, if you are unsure as to the trigger words for your specific domain, try A/B testing a few examples to narrow down the culprits.


ALL Sale Tops from $15 Each When You Buy 2 vs You Can’t Top this…

Ultimate Dress & Shoe Sale 👗Styles from $35 vs 👗Power Couples👠: Dresses & Shoes from $35 

HRS Left: 1500+ Flash Sale Styles Under $50 For Her & Him vs OMG have you seen this ⚡ Sale? It Ends Tonight.

$20 Off Boots | Boots @ $25*! Kick up your style! vs Kick up your style👢Boots from $25

FLASH SALE: Everything under $50! Ends Tonight! vs It’s all over tonight, don’t miss out

Issue 2

Repetitive Email Content

The Culprit

When emailing customers, if the content is not “fresh” ISPs may pick up on this and put you in a spam trap. This is often seen in “reminder” type emails where the visuals/ content within the email are not very different from previous sends and may look like you are bombarding clients with the same message over and over again. 


If you are already not doing so, try segmenting your database for these types of emails by excluding users who have already seen the previous email. Bucket customers into segments like “Opened but did not click” , “Opened and clicked” and “Did not open” (use automation in Salesforce Marketing Cloud or Pardot to make this task easier). Also, whenever possible, try re-arranging the content in your emails so it does not appear to be an exact replica of a recent send- or better yet, use totally new copywriting, ALT tags and images for best results.


Less of this:

email deliverability best practices

And more of this:

Issue 3

Poor Sender Score

The Culprit

Sender Score is a number between 0 and 100 that identifies your sender reputation, kinda like your email “credit score”, but in this case it’s how mailbox providers view your IP address. Factors such as spam complaints, unclean sender lists, engagement % and industry blacklists can all contribute towards this score- which in turn affect your deliverability. Sender Scores of 90 and above have complaint rates under 1%, unknown user rates under 2% and on average spam trap hits of 0.40 or less- making them excellent senders. Sender Scores of 10 or below have complaint rates of 7% or more, unknown user rates above 7% and on average spam trap hits of 7.5% or more- making them poor senders.


Pretty simple really… keep your sender score as high as possible. Regularly clean your sender list and remove invalid or hard bounced email addresses (quality > quantity)

Have a clear opt-in policy or employ a double opt-in procedure to make sure the emails you do have on your list have consented to receiving communications from you. This is especially important when importing large email lists from other marketing initiatives such as store events or new collaborations/ partnerships. 

Track bounce rates and bounce codes (DOA, Soft, Hard, etc.) to detect an issue early on and adjust accordingly. 

Make sure your email content is relevant and engaging to avoid low open and click-through rates.

Finally, when starting off with a new domain, be sure to employ an IP Warm Up plan so that you are not blasting tons of new emails all at once and appear spam-like


Websites to Check Sender Score






https://gmail.com/postmaster/ (Gmail Specific)

So getting to the inbox is half the battle, and these quick checkpoints should help diagnose a potential issue with your domain. Be sure to monitor deliverability rates before and after each initiative to adequately track what works best, so you can continue to optimize on an ongoing basis. Happy emailing!