15-20% of your email marketing efforts go to waste.

This is the percentage of your emails end up in junk folders or remain “undelivered” on average, based on data from Return Path.

Improving Email Deliverability Key Takeaways

In a hurry? I’ve got you, don’t worry.

Here’s the tl;dr version for the time-poor sales or marketing person

  • User permission-based email lists – it’s best practice and, in some cases, literally the law
  • If you’re going to cold email, target, and segment as accurately as possible
  • Authenticate your domain with your email service provider
  • Keep your email lists cleaned
  • Watch your language and avoid trigger words in body and subject line
  • Keep your emails simple – avoid complex HTML or too many links
  • Include an unsubscribe link
  • For new domains, start with smaller campaigns and gradually increase the volume
  • Use trigger-based emails in addition to one-off “blasts”
  • Be mindful of text-to-image ratio – aim for 70% text to 30% image
  • If you have to buy a list, clean it

Email deliverability is one of the most influential metrics for your email marketing programs, potentially more important than the exact design template or CTA copy you choose.

Email deliverability rates vary greatly by country and by email platform. (Many popular email platforms only deliver 75-80% of the emails you send). But independent of the email tool you pick and region you send emails to, there are steps any marketer can take to increase the share of emails that reach inboxes.

In a way, email deliverability is like the credit score for your email marketing programs. Life is pretty good with a good credit score but you need to make an effort to maintain it, and you have to stay out of trouble.

How to measure email deliverability?

Unless you’re starting from scratch you may want to establish a baseline on where you stand with email deliverability.

If your “opted-in” audience open rates are 40% and up and click rates 4-5% and up, your email deliverability is probably fine. For cold emails, this benchmark is probably 15-20% for open rates and 2% for click rates.

Additionally, it’s good to run a quick deliverability test for your email setup.

A tool like Mail tester is great to test email deliverability. You get a quick score and a summary of the key aspects that influence deliverability like email domain reputation, message formatting, domain authentication, and email content. Unsurprisingly, we’ll cover these aspects later in this post.

All email marketers monitor open and click rates. We’d suggest to also monitor email bounce rate regularly (more on that below) and run a test like Mail-Tester every now and then, and every time you’ve made major changes in your email templates or tools.

How to improve email deliverability if you’re not a technical expert

Below is a list of 11 tips any marketer can and should follow to improve deliverability.

(Scroll down for further recommendations to technical pros)

Tip #1. Only send emails to people who expect to receive emails from you: get permission

This first tip is more of an attitude or approach than a technical tip, but it has a really big impact on deliverability. If you only send emails to people that expect to hear from you, your need to follow the rest of this article gets dramatically smaller.

There are also good legal reasons to get consent before you send a campaign.

Ideally, you’d want “double opt-in” before you start emailing someone ie. new subscribers are sent a confirmation email. This way you can make sure people who are not actually expecting to be emailed are maliciously or accidentally added to your list.

Tip #2. Segment your cold list (aka the other option to send emails to people who expect them)

In an ideal world, prospects will have visited your website or event booth and given you consent to keep them warm via email. As we all know, the world is not ideal.

While we’re firmly against spamming at Outfunnel, we’re also realists and know that in most situations prospects haven’t self-identified themselves.

The difference between smart cold emails and spamming? Segmentation.

If you’re scraping your list, put extra effort into defining your criteria. Test assumptions on a small number of contacts before blasting tens of thousands.

Tip #3. Authenticate your domain with your email tool

Email providers, like Yahoo and Gmail, use DKIM and SPF records to verify that the sender (so, in this case, you) has permission to use this domain and isn’t a spammer.

Every email marketing tool typically has its own steps you’ll need to follow in order to set up DKIM and SPF verification.

These steps typically involve adding a DNS record. You’ll need to have access to your DNS account (usually, this is provided by your web host).

Once you’ve set everything up you can use a tool like MX Toolbox to verify that you’re good to go.

Tip #4. Clean lists regularly 

Email bounces can really hurt your sender reputation, so remove any “hard bounced” email addresses, ASAP – something Outfunnel handles automatically.

Circumstances change and people who sign up to hearing from you a year ago may have moved on. Also, many email service providers now use machine learning to monitor at scale whether recipients engage with emails.

So, if you see someone isn’t opening your emails anymore, remove them from your list. That way you can head the robots off at the pass, avoiding damage to your sender reputation by sending bouncy emails.

It’s also important to consider volume over time.

Say, for example, you send 5 emails in one week, none of which have been opened. In this instance, you can safely assume that this person may be on holiday. Conversely, if someone hasn’t opened an email in 4 months, but you’ve only sent one, that doesn’t mean they don’t want to hear from you.

A good rule of them for this situation is this:

If you’ve sent at least 5 emails over the last 6 months and got 0 opens, it’s time to remove those addresses from your list.

And, of course, you don’t have to remove them straight away. You can always move them to a “dormant” segment and try to warm them back up with an email list reactivation campaign.

Tip #5. Avoid words that trigger spam filters in subject line 

If you’ve ever taken a glance at your spam folder you’ve probably felt like 75% of it is people desperately trying to sell you some viagra. Well, sadly, spammers have all but obliterated the hopes of any legitimate online viagra salespeople.

Words like “viagra”, “f r e e”, and dollar symbols are all going to hurt your deliverability. As will writing your subject line in ALL CAPS or including too many exclamation points(!!).

When it comes to the body copy, similar rules apply:

Avoid spam trap triggering words (Prospect.io has a great list) and using red text.

Tip #6. Use common sense and avoid unreasonably complex design or HTML

Avoid sending very short (or very long emails) if you don’t want to get grabbed by spam filters. Email service providers will also check to see whether the code is suspicious (either deliberately malicious or just plain garbage-looking).

If the email doesn’t look and feel like an email, it isn’t going to make it to the inbox.

Keep formatting basic, avoid adding loads of tracking and keep things as clean and simple as possible.

Tip #7. Offer a way to unsubscribe 

This one perhaps splits email marketers.

People coming from the sales side say that an unsubscribe link makes emails appear less personal and can trigger filters that land an email in the Promotions tab or even Junk folder.

We disagree, vehemently.

People need a way out that doesn’t involve them having to jump through hoops, so including an unsubscribe link is the ethical thing to do. Not only that but in many parts of the world now you’re legally required to add a link.

Even more importantly, adding an unsubscribe link is good for email deliverability in the longer term. Why?

If you don’t add an unsubscribe link and the recipient doesn’t want your emails, do you think they’re going to email you back, kindly asking you to stop emailing them? No, they’re going to mark you as spam or report you.

So, add the unsubscribe link, particularly if you plan on sending more than one email or campaign.

Tip #8. Warm-up your domain

If you’ve just switched to a new email marketing platform or have just started sending email marketing emails, then you should take the time to “warm-up” your domain.

Also known as IP or reputation warming, is a way of improving your reputation profile when you start out, your list should, ideally, be small and active.

The reason being is that engagement, like opens, clicks, and replies are all positive reputation signals – so a smaller list of more active recipients is going to give you a better ratio of active, interested parties.

If you kick things off with a 10,000 email blast to people who’ve never heard from you, your deliverability is going to be terrible and you’ll risk trashing your reputation. Instead, take that list of 10,000 contacts and break it up…

Week 1: 250 recipients
Week 2: 500 recipients
Week 3: 750 recipients
Week 4: 1300 recipients, etc…

Tip #9.  Triggered and event-based emails, not just blasts 

Trigger-based emails have higher engagement rates than a one-off, mass email blast.

As engagement is a positive domain reputation signal, you should use trigger-based drip emails to reach more engaged people.

You can, for example, set up web visitor tracking to see what pages your customers are viewing and use that to trigger an automated, targeted email. Firstly, you know they’re awake (always a problem when sending mass-mails), you know they’re either on their phone or computer and you know they’re thinking of you.

By combining automated email sequences, with one-off campaigns, you can keep your audience happy and improve deliverability

Tip #10. Keep a healthy text-to-image ratio

Always keep in mind how many images vs text you use in an email. If your email content is more than 50% images, it can set off spam filters.

Same story if your images are too big.

Aim for around 60% text to 40% images, or ideally 70% to 30%

Tip #11. Don’t buy lists from shady providers and even then, clean the list before using.

OK, I said don’t buy lists, but I exist in the real world.

Email lists are going to be bought and sold and this article is about email deliverability, not the merits (or lack of) of bought email lists. And many list providers are reputable and sell good-quality data, perhaps even with contacts having given consent to be contacted.

So, let’s say you’ve already bought that list from a reputable source…

Before you put those addresses anywhere near your email tool, run the whole list through a list cleaning service (or, maybe even several). If you don’t, best-case scenario, you end up with a very low-quality list.

Worst case scenario, your email gets caught by a spam trap address and you end up on some kind of blacklist.

Extra tips for pros for improving email deliverability

Bonus Tip #1. Set up feedback loops

If you’re sending a lot of emails, people are going to complain at some point.

So, it’s important you have access to that feedback so you can pick up problems and fix them before you end up with a dent in your domain reputation.

This is where email feedback loops come in. In short, a feedback loop allows you, the sender, to receive notifications when someone complains about your emails, say by marking them as spam.

Many mailbox providers have different procedures for setting up feedback loops. In the case of Gmail, there’s Google Postmaster Tools plus ReturnPath offer a Universal Feedback Loop that allows you to monitor complaints from lots of different providers.

Please note that if you’re using Outfunnel, we’ve set up the necessary feedback loops and, should your account generate lots of complaints, we’ll proactively let you know.

Bonus Tip #2. Test and monitor email deliverability

If like us, you send a lot of emails, or if email forms part of your core product, you should really be testing and monitoring your email deliverability.

At Outfunnel, we use Glockapps to provide us with constant email deliverability monitoring (not surprising, given email is a key part of our platform). GlockApps give us deliverability stats by ESO and country and provides recommendations.

Bonus Tip #3. Check your sender reputation

If you send a lot of emails and want to make sure that there are no reputation gremlins that could be lurking, there are some tools you can use to track potential issues.

For example, Talos Intelligence allows you to check your domain or IP and see whether it’s been flagged as spam, legitimate email or malware.