Email deliverability is one of the most important factors to a successful email campaign. If your emails are not getting delivered, then all that hard work you put into the email design and copy was a waste of time and money. According to a study by Return Path, one in six emails never reaches the inbox, instead going to junk folders, or getting bounced. The good news is that you can improve your email deliverability rates. Here are 8 best practices for email deliverability to make sure you are taking full advantage of your email marketing efforts.

1.   Use Double Opt-in Email Addresses

There are two kinds of opt-in email addresses you can use for your campaign: single opt-in and double opt-in. The best way to defend yourself against spam complaints is to use double opt-in email addresses. The difference between double and single is that with double opt-in, also called confirmed opt-in, people get a confirmation email after they have submitted their email address. They are not actually subscribed and opted-in until they click a confirmation link in the confirmation email. In a single opt-in, the person agrees to receive an email by submitting their email address and simply checking a box, or leaving a pre-checked box checked. This may seem like a good way to harvest email addresses, but it can backfire and generate spam complaints. The Canadian Anti-Spam Law actually doesn’t allow pre-checked boxes in emails.

2.   Purge Your Bounces

If you are sending your emails to non-existent users, you will ramp up your bounce rate and ruin your credibility! Take the time every now and then to remove email addresses that have resulted in hard bounces and soft bounces. A hard bounce is a permanent failure to deliver an email due to deleted, invalid, or blocked email addresses. Email addresses that result in hard bounces can negatively impact your email deliverability. Email servers keep track of bounces and can suppress the delivery of your emails if you trigger too many hard bounces. Soft bounces occur when an email is sent to an email account that is full or temporarily unavailable, such as the server being down. Although soft bounces aren’t as serious of a problem as hard bounces, if you keep getting them, you should take that email address off your email list.

3.   Clean Out Unsubscribers and Inactive Users

Make sure you comply with unsubscription requests immediately. CAN-SPAM and CASL allow up to 10 business days for emailers to follow through with the requests. It can be disappointing, but remember, just because someone unsubscribes doesn’t mean they are a lost cause. Make it easy for people to opt-in to your email list on your website, blog and/or social media. You never know when they will change their minds. Also, it’s a good idea to remove inactive subscribers from your email list, just like unsubscribers. If a person hasn’t read or opened your emails in a while, it’s time to let them go. They are not valuable subscribers.

4.   Don’t Send Too Many Emails

Sending too many emails can annoy subscribers, which can cause emails to end up in the trash or worse, spam. According to research by MailChimp, the more frequently a company sent an email, the lower the click-through rate was. However, one marketer’s definition of over-mailing can be another company’s everyday practice. There really isn’t a “right” number of emails to send. The only way to figure that out is by testing and seeing what works best for your audience. As long as you have good content and are consistent with your schedule, there’s no wrong number or frequency.

5.   Avoid Spammy Trigger Words

If you searched “list of spam words” on Google and tried to not use any of them in your email, you wouldn’t have any words left to use! That being said, try to use them as little as possible, don’t write “FREE” in all caps in your email subject line or write the body of your email using big, red capitalized letters. Here’s a brief guideline you can follow to help with better email deliverability.


  • Use phrases like “Click here!”, “Free!”, and “Once in a lifetime!”
  • Use excess exclamation points!!!!!!!!!!!!!!!!!!!!
  • Use bold red fonts

6.   Implement Responsive Design

According to the US Consumer Device Preference Report, up to 65% of emails were opened on mobile devices in 2014. With the majority of emails being opened on mobile devices now, it is crucial that emails use responsive design to optimize email content that is viewed on smartphones and tablets. Responsive design readjusts email designs (font size, image size, layout, etc.) to adapt to different screens on different devices. Without responsive design, the viewer will be faced with the inconvenience of having to zoom or scroll to see the email, and may end up marking your email as junk out of annoyance.

7.   Strive for a Good Text-to-Image Ratio

An image-heavy email can increase the chances of the email being flagged as spam. As a general rule, the best way to avoid the spam folder is to make sure that you emails reflect a balanced text-to-image ratio. A lot of email clients, like Outlook, block images by default, which means the viewer has to manually unblock to see the images. With this in mind, it’s important to include text. Try summarizing the main point of your message: the offer, the announcement, etc. Some text, especially the main CTA, should be viewable upon opening the email, even if the images are blocked.

Managing and optimizing email deliverability requires dedication, time and energy. Although the steps to good email deliverability aren’t difficult, it can be demanding work. However, working with an email service provider or email broadcast service like US Data Corporation can help cut down the time-consuming work for you. For additional advice on how to make your email more deliverable, read our white paper or contact one of our email marketing experts at (888) 578-3282.