The Complete Guide on Email Deliverability

Marketers love email and keep on loving it forever. For all of the advancements in technology, email is still among the most important and effective channels in a marketer’s arsenal. That’s the reason email deliverability is so crucial.

When you’re anticipatorily sending emails to customers and prospects, the spam folder proves to be your most feared enemy.

Legitimate emails hitting the spam folder or not even making their way to the inbox keep you awake at night. Undoubtedly, your low-end email marketing program allows you to create compelling emails for very little to no money.


However, the big thing you’re now ignoring is the crucial part of the email: it’s delivery. So, In this article, we’re exhibiting fabulous tips to increase your email deliverability, and these are all easy to follow.

Delivery vs deliverability

To begin on the right foot, you’ll first need to understand how email delivery and email deliverability differ. There is a bit of overlap, but compulsorily in marketing and sales, those two should be considered individually.

Email delivery is the operation between hitting “send an email” and the point of time it pops up in the receiver’s inbox. It’s all about speed and inbox placement. Now, when we discuss how your email traveled from your CRM system to the customer’s mailbox in just 4 seconds, you’re actually talking about email delivery.

Let’s clear it.

Email deliverability, on the flip side, goes way beyond swift delivery and pays attention to the inbox placement. We can call Email deliverability the ‘science’ behind emails ending up in the inbox. It includes clean recipient lists (as few bounces as possible), domain reputation, and a few authentication methods to be cleared on who you are as an email sender.

What’s the basic need of improving deliverability?

For improving your email deliverability, you have to think like the guys that make email possible, which are the Internet Service Providers (ISPs). Now, to do that, you must understand the extent of what ISPs actually deal with daily.

Question: How many emails are sent worldwide each day?

Can you guess that?

It’s around 270 billion; you can increase or decrease a few billion. A bit more than half of those 270 billion are business emails, while a bit less than half are consumer emails.

Just concentrate on that number for a minute, and then concentrate on the fact that that’s actually a daily number.

So, what percentage of those emails are spam? Would you believe me if I say that it’s around 50%? Well, it’s true – more than 100 billion spam messages are delivered every day.

Now, that’s a true tidal wave of spam, attempting to make its way to your inbox (and everyone else’s).

ISPs are truly tremendous at managing this neverending assault of spam. They ensure spam doesn’t even reach your spam folder. By doing so, they’ve displayed themselves as real heroes to email recipients.

But they need to be somewhat ruthless to do their task. They have to punish bad spending habits. Just put yourself in their shoes, and feel that they’re dealing with huge volumes of emails sent from malicious senders. Honestly, would you act differently? Certainly not.

Now here’s the main word!

Try to think like an ISP If you truly want your emails to be perfectly delivered. Keep in mind, they’re familiar with the history of your mailing list, and they track which emails have been clicked by your receivers and which haven’t.

They also know when someone opened one of your emails last time. And in case no one is opening your emails, you’ll wind up nowhere else than in the spam folder…or your email won’t even be delivered at all.

What’s the core objective of email deliverability?

Now, that question might seem pretty simple. Getting your email delivered is the main purpose of email deliverability, of course. But it isn’t that simple.

For example, your latest emailing evaluation report exclaims you have a 99% deliverability rate. Now, that sounds amazing, right?

But deliverability rate proves to be misleading sometimes. It’s missing one crucial point.

Just getting your emails delivered isn’t the only thing you wish. You want to get your email hit your customer’s inbox (and further, read also).

Email that enters any customer’s spam or junk folder is still counted as delivered. Delivery rate reflects nothing regarding inbox placement. Focus on inbox placement rather than fooled by high delivery rates.

How do you get amazing inbox placement? You need to cherish the full journey of an email.

Here’s the journey:

  • Your email gets sent out to the destination server.
  • Email reaches your recipient’s email server.
  • Recipients email server checks your email content and metadata
  • Email gets blocked or delivered as per recipient server filters.

What’s considered A Good Email Deliverability Rate?

Now, that’s something tough to define. But according to a campaign monitor research, 1.29% and 0.69% respectively was the average bounce rate of emails for the marketing and retail industry.

This shows that in case almost 2% of your emails are bouncing, there’s nothing to worry about. Hence, your email deliverability rate needs to be above the 98% limit. But your bounce rate is touching anything between 5 or 10%; it’s something to worry about.

So the question comes, what all impacts your deliverability rate and email bounce?

Best practices for email deliverability

You anticipate all this work to ensure your domain and IP address have a good reputation. You implemented a sender policy framework, avoided spam traps and blacklists, scrubbed your email list clean of addresses linked with high bounce rates, and so on.

Email deliverability is undoubtedly a heavy part of the equation. However, the other part is ensuring all this effort doesn’t go in vain. Your emails need to be frequently delivered and, in case you’re lucky, read.

At that point, the thing to avoid most is spam complaints, as they’ll attack the sender’s reputation and rupture the foundation of the email deliverability. Spam complaints are inevitable because many people mark emails as spam which they don’t want to read, unaware of the negative repercussions this step has on a sender.

In case you’re guilty of this, just mark individual emails that you don’t care to look at as read or delete them. If you no longer desire to receive any emails from a certain sender, just unsubscribe. To preemptively combat spam complaints, you can include the following email deliverability superb practices while building your email lists and campaigns:

Get permission—the pure and honest way

Just think of it, Asking someone for their email address is entirely different from asking for permission from them to send them an email. This subtle but crucial distinction highly influences deliverability.

In case the process of address collection doesn’t include actually asking for permission to send new users marketing emails, your open rates will suffer deadly, or they’ll be attacked by high spam complaint rates.

Downloading an app, accessing any website, creating an account, or setting foot into a contest are all inadequate and deficient substitutes for just….asking.

Rather than bury a blurb somewhere in the terms and conditions regarding reserving the permission to send marketing messages, etc., prefer telling people that you’re gathering addresses for ongoing communications, and you should make their participation optional as well.

When the subscription is bundled into another agreement or mandatory, open rates plummet and throw your emails into the spam folder. Avoid such gimmicks in the first place, as it’s much easier than digging your way out of the deliverability issue.

Set expectations, and then meet them

Explicit concur, while compulsory, is still just the best practice (baseline practice, actually) for email deliverability.

What separates superb results from just ordinary ones is fulfilling the expectations of the subscribers after clearly showing what those should be.

If you write “Sign up for our newsletter,” it would just cover the basics, and somebody entering their email address in the box beneath that phrase would certainly expect to hear from you. “how often they’d hear from you” is a fact they would be unaware of.

The newsletter is an amazing way to hear from any brand, but product announcements, special discounts, and early access to sales are even more enticing.

Subscribers who are offered the power to dictate the frequency of receiving your updates are less likely to unsubscribe or complain. If you eliminate the guesswork out of your subscription process and offer subscribers some control, the payoff is going to be worth the extra effort for sure.

As a bonus, collecting subscribers’ names, areas of interest, and locations, can be instrumental in targeting certain audiences to drive conversions with greater precision and can also help pinpoint the core source of deliverability problems in case they arise.


There are several mass email senders facing problems with email deliverability. In many cases, a new account gets blocked just after sending a mass email to a minute list consisting of 100 recipients.

Yeah! It’s a harsh truth.

It happens, the first thing for a mass email sender to know is to authenticate his/her email account. Authenticating your email account can be compared to providing a driving license and letting it move ahead on the road and reach the receiver. Total 4 sorts of authentications are needed to send mass email without getting your email account blocked and straightaway landing on the recipient’s inbox. Here they are:

  1. SPF
  2. DKIM
  3. DMARC
  4. Custom Domain

SPF(Sender Policy Framework)

In simple words, the main job of SPF is to permit the Domain’s admin to define the mailing servers’ list used from the Domain.

SPF generates a record in your Domain Name System, which lists down various servers that possess the authority to send emails from a domain’s behalf. Besides that, the record specifies how recipients must handle emails sent from unauthorized servers.

Whenever a sender shoots any email from a domain authorized by SP, the ESP of the recipient checks the SPF authentication and offers a green signal to the sender’s Domain.

2 DKIM(Domain Keys Identified Mail)

Here comes another email authentication process specially designed to detect email spoofing.

With your DNS records, DKIM offers an identical digital signature, which helps the ESP of the sender to verify that the email is received is from a high-authority source. Adding the DKIM records in your DNS will boost your email productivity and help you from staying away from several major email scams.


DMARC (Domain-based Message Authentication, Reporting & Conformance) isn’t a necessary authentication process, but it’s a good-to-have authentication process that helps improve email deliverability.

DMARC records utilize your DKIM and SPF records to assure the ESP of the receiver that no fraudulent activities are accompanied by the email. On a few occasions, the Internet Service Providers restrict a few IP addresses or Domain Servers as well.

4 Custom Domain

It won’t be wrong to call Adding a custom domain a “trick” to improve email deliverability. ESPs usually blacklist the tracking links, and that’s the reason tracking links in the email body push your emails to the SPAM filter.

Offering a custom domain changes the actual tracking domain with your customized Domain that’s safe to use and isn’t blacklisted by any ASP. Usually, proper email automation tools such as SalesHandy permit adding a custom domain to your links and improve your email deliverability.

Check On Your Sender Reputation

Email Service Providers decide a score according to your IP address, and domain score is what we call sender reputation. A higher score means better email deliverability. How can you increase his Sender Reputation? Here are the crucial factors:

1) Warmup your email account after authentication

Although after authentication, you’ve got a license to deliver your emails to your recipient’s inbox. But we’d never suggest sending humongous email campaigns from your new email account. You need to start slow and then grow gradually.

If you send a huge email campaign at your first take, your account might straightaway come under the vigilance of your ASP, and this can highly affect your email deliverability. This might end with permanently blocking your account also.

Just begin by sending individual emails and driving conversations. You need to follow this practice for some days and gradually increase this number. Email Warmup helps in elevating your sender reputation score besides making your account healthy for email campaigns in the upcoming time.

2) Maintain Sending Quota

No matter whether you’re permitted to send emails in bulk after authentication and warmup, you still need to keep a proper track of the number of emails you’re sending in one day.

If you pull out a lengthy list of recipients and begin sending emails without keeping a count track, your emails might begin getting blocked. We recommend you never exceed your email quota.

In case you exceed your email quota every now and then, your email service provider will start keeping a sharp eye on your activities, and this might get your email account blocked temporarily or permanently. Just make it a practice not to cross the email sending limit.

3) Stay Aware of Email Blacklists

It’s a real-time database that figures out which emails are SPAM and which all are valid. Domains or IP addresses that are doubted of sending SPAM emails are called Email blacklists. We’ve listed a few amazing tools at the bottom of this article.

Currently, we’re discussing Email Blacklists, and these are of two broad types:

  • IP Address Based:
  • These are the list of networks or IP addresses that are consistently used to send abusive content for SPAM contents.
  • Domain Based:
  • These are the domains’ list of those who misuse the domain by shooting SPAM or get involved in any phishing activities.

You should constantly check your IP and domain address. If it’s blacklisted, you need to start warming up your domain (as explained above) once again and make a whole fresh start.

4) Feedback loop

Often, email service providers let senders gather feedback from unsubscribing recipients by simply redirecting them to complete forms or short surveys. This enables you to build a successful feedback loop that helps you stay in touch with your users’ requirements.

When any recipient doesn’t desire to stay subscribed to a specific sender, they can narrate feedback to the sender about the reason, generating meaningful engagement. The feedback loop highly helps in email deliverability In the long run. This way, the sender can maintain a cleaner and more valuable list of recipients.

5) Email List should be verified.

Getting a list of recipients is not a difficult task. Email addresses of your recipients can often be invalid or expired. So it is always suggested to verify the subscriber list with a verification tool. A verified Email list decreases your bounce rate, increases your email deliverability, and also your sender reputation score.

Generally, after verifying your recipient’s list using any tool, it divides your recipient’s list into 3 types: Risky, Valid, and Invalid.

  • Risky: These are the existing contacts that aren’t safe to send due to a lack of engagements in those accounts.
  • Valid: These are the verified contacts that are safe to send.
  • Invalid: These are expired or non-existing contacts, and we suggest not to send emails to them. The emails delivered to these addresses are called to bounce.

6) Stay away from Email Bounces

Getting emails bounced is something no one wants. Still, 9% of business emails face this.

Bounced emails are equivalent to lost opportunities despite all the efforts. Besides that, frequent bounces may make a sender’s domain enter into a blacklist and/or get blocked by the ESP.

There are 2 sorts of bounces –

  • Hard Bounce: Hard Bounce take place when your recipient’s email address has expired, doesn’t exist, the domain is invalid. A hard bounce is a permanent bounce. Sending an email to such an email address isn’t possible. You must remove such email addresses from your email recipient’s list.
  • Soft Bounce: Soft Bounce takes place when the recipient’s inbox is full, or the file size of the email you delivered is humongous, or any other temporary problem. These bounces take place for a short time duration. However, if you fail to send emails to such an email address after numerous tries, you must remove the recipient from your email list.

Target The Most Engaged Audience

Engagement in your emails is a major thing that improves your sender’s reputation. The more users click open, read, and tap on your emails, the higher your sender reputation is going to be.

So the question is, how to elevate the user engagement on your emails? Well, by targeting specific audience groups. Just target those users who’ve engaged with your brand many times before. You need your email marketing tool for this and create a segment for consistent buyers or those users who’ve bought something from you 2-3 times before.

After dividing users into special segments, write personalized copies and send them to those users. In case the users associate with your emails, they’ll certainly open them, go through them and offer you more engagement.

Include a double opt-in strategy

If you want to lower unsubscribes, and reduce bounce rates, just adopt a double opt-in strategy. Most importantly, the reinforcement results in lesser spam complaints.

But how? The meaning of a double opt-in means that once somebody has signed up to your email list, he/she receives a confirmation link which is supposed to be clicked to officially receive your messages.

Normally, it requires a bit of extra effort from recipients. However, by confirming they’re opt-in, they ensure that they genuinely desire to receive your campaigns, and the chances of them marking your emails as spam is less.

Plus, double opt-ins separate real email addresses from fake ones because a spam address actually can’t confirm the second opt-in. You won’t end up on any blacklist for accidentally emailing a spam address.

Master your sender names and subject lines

Judging the books by covers is simply prohibited (LOL), but what about the poor emails? Subscribers always judge a book (which is your email) by its cover (your subject line).

It’s super crucial that your subject lines and sender names capture attention in a non-spammy manner. For beginners, your sender’s name or email address shouldn’t even explicitly mention “don’t reply” because it’s too insincere and could certainly lead to subscribers simply flagging your email as spam before opening it.

Just include a disclaimer in the message’s body if you desire not to respond to replies or are unable to do that. Just try to humanize your sender because it actually works. Feature the name of a specific figure at your company, or just feature your company’s name with a properly matching email address.

For subject lines, avoid using all-caps, FWD: or RE: as Spammers use this technique often because it’s highly effective at grabbing attention. Pay attention while narrating subject lines for your emails.

Ensure not to use spam words like ORDER NOW, PURCHASE, ONLY, FREE, etc. However, ISPs, subscribers, and inbox providers have grown weary of such sort of subject lines for that same reason and will classify such emails as spam without thinking twice.

Maintain consistent frequency

If you always send two emails per week, switching to four can negatively impact your sender’s reputation. Subscribers familiar with your cadence will notice the change and assume email bombardment is on the horizon, which could result in a spam complaint.

Temporary modifications to your frequency for holidays, special events, or a limited series happen, but ongoing inconsistent sending is what you want to avoid.

Feature mobile-friendly, consistent design

Another spot where consistency influences email deliverability: Content and Design. Your website appears a certain way as it embodies the identity of your brands. Your emails need to mirror that identity, too. Confusing subscribers with non-cohesive branding does nothing good; it could lead to them simply marking your email as spam, which you actually don’t want.

Also, like your site, your emails need to be mobile-friendly. Over half of email opens take place on mobile devices, and a deficiency of mobile-friendliness can lead to a spam complaint. Several inbox providers auto-optimize for mobile, closing the doors of excuses for your delivered emails to not be compatible.

Include plain-text/HTML versions

Did you ever open an email with the images not automatically loaded? Exactly! Not all inboxes are equipped enough to receive your gorgeous-looking campaigns, which is the reason you must include a plain-text version.

Inbox providers and ISPs look favorably on plain-text emails as they know exactly what’s inside the email. Recipients will still receive the primary message you want to communicate, eliminating any reasons to put your email in a spam box.

Visuals in Emails

Emails are truly valuable and targeted pieces of communications that are rolled out with an intent to stir up a desired reaction from the customers.

Our attention span has reduced to a few seconds and expecting your readers to easily spot your email, click it among an ocean of emails, and also remember it is truly too much to ask for. Shall we make it easier for you now?

Designers and traditional marketers desire to include heavy usage of visuals and images for both branding and aesthetic purposes. Simultaneously, Email marketing specialists have to minimize email images for display and deliverability reasons. Balanced use of images and graphics that can convey the intended message rather than using much text is a fairly win-win affair!

How to Use Visuals in Your Emails with all perfection?

1) Avoid using one BIG image that structures the whole email or all image files

On how many occasions have you received emails that display broken image icons all across it? No matter your images might be highly attractive, many of your recipients might simply end up with emails where your images haven’t got downloaded because of incompatibility with their mail servers or slow connection.

Further, as there’s nothing mentioned in the first couple of inches of your email that shows something about the images, there’s not a single reason for them to download the first time.

2) Don’t use images in the starting of the email

Image your inbox reaches your user’s inbox. Along with various other emails that have reached into his/her inbox, your email displays the subject line, surprisingly followed by nothing else.

3) Use smaller size images and only where compulsory

Image-heavy emails may force the server to ruthlessly throw your email into the deep dark Spam folder. Uhuh, we never want that! Use smaller size images that never overshoot the text density in your email.

4) Avoid trapping crucial messages in images + Use text links

For example, using an image of a CTA button will definitely go south in case it doesn’t download, and the user misses it. Making him click, it was the WHOLE POINT, which just failed!

Use preset buttons offered by your email service provider, or you can complement it with a normal text link.

The use of visuals is pretty crucial to convey crucial information most effectively. However, you need to be prudent in your use of images while creating an email to avoid getting listed as a spammer.

Avoid shortening URLs

Avoid using shortened URLs while using external links in your emails. They are convenient for sure but don’t forget they hide a link’s destination, and that’s the thing spammers use shortened links so much.

If you’re worried full URLs will destroy your email’s look, include hyperlinks, which are clickable words linked to an external URL. They’re much more visually appealing in contrast to URLs, and the chances of clicks are also high.

Build A Trustworthy IP

A valid and trustworthy IP is that which isn’t counted as spam by the ISP filters. How do such filters add an IP to the spam list?

Simple, by analyzing the spammy keywords, subject lines, and content. If you send emails containing spammy content or keywords, ISPs will block your emails, and that hurts your IP badly.

Send a small bunch of emails to the engaged email addresses to build a valid IP

If those emails perform well, attain good click-through and open rates, you can begin increasing the number of emails and further send them to others.

Email Deliverability Testing Tools

Before you send a mass email campaign, you need to test email deliverability at all steps for knowing your domain health and email sender score. Here we list some of the superb tools that will be useful for testing email deliverability.


Myemailverifier is an all-in-one sort of tool, which actually strengthens the base of your email marketing campaigns to the next level. It’s basically an Email verification service, which filters your email list and offers you just the real addresses.

This tool is closest to perfection, and the accuracy percentage is the max in the current marketing. Free trial is there, but the tool itself isn’t free, but no worries, as prices won’t hurt you. If you’re serious about your email verification and deliverability, then MyEmailVerifier is the best choice.


ZeroBounce offers an email deliverability toolkit, helping you improve your email performance. They offer two main tools for performing deliverability tests before sending.

First, the email server tester finds any potential problems with your email server and lets you fix them before launching your campaign. Then, the inbox placement tester offers you an idea regarding where your email will land ( spam or inbox). This can be your one perfect solution for testing your emails before approaching to send them.


Mail-Tester doesn’t charge you anything to check all the well-detailed aspects linked with your domain and email content. Just send an email with your content to the similar email id offered by the mail-tester, and then the mail-tester will offer all the details of your email authentications and contents.


Glockapps is pretty much like Mail-tester but with several advanced features. Checking whether the emails have landed in the inbox or SPAM box for various Email Service Providers is so easy with this tool. With the Glock app’s premium plan, you can do an entire email deliverability test and receive a report of email subject line, Authentications, blacklists, and email body content.


Mxtoolbox is a famous tool used by several email marketers to elevate their email deliverability. This tool offers all types of tests concerning your domain health and DNS. It’s also widely used for testing the blacklist score because it shows relevant results.


Sendcheckit is a perfect subject line testing tool that helps you to check your subject line’s spam score and also offers simplified suggestions regarding improvement of your subject line for attaining better email deliverability.

DKIM Validator

DKIM Validator is a simple and free tool to check your authentication besides improving your email deliverability. You can check whether your DKIM and SPF are correctly working or not by using DKIM Validator. Along with that, it can display the SPAM score of your email content through SpamAssassin.


Using ISnotSPAM, you can detect SPAM content in your email body. Simply send an email to the similar email address that ISnotSPAM provides, and you can get the spam score and various details about improving your content. It lists down all the checklists that generally get hit into the spam filter. This is an essential email deliverability tool.

Email deliverability recap

Email deliverability means much more than just reaching your subscribers. You could certainly reach your subscribers as spam, but that’s certainly not what you want. You want to hit their inboxes, and to achieve the same, you must consider numerous factors affecting email deliverability:

  1. Ensure your IP address and domain has an amazing sender reputation, so inbox providers and ISPs will let your email reach inboxes.
  2. Stay safe from spam traps by not buying email lists. Oftentimes, list companies scrape their data from the web, and such data may be “seeded” with fake, bad, or inactive email addresses. Buying email lists and sending emails to various recipients who haven’t “opted in” is certainly the easiest and quickest way to become a part of the blacklist.
  3. Check your feedback loops to detect spam complaints. Immediately scrub such subscribers, besides invalid, inactive, and spammy email addresses from the list to reduce your bounce rates as well as negative blows on your sender reputation.
  4. Implement DKIM and SPFs signatures so inbox providers and ISPs can verify that you’re permitted into the desired inbox.

After getting in the inbox once, here are the email deliverability best practices you must follow to ensure your emails mark a permanent residency:

  1. Design a double opt-in strategy.
  2. Use an easily recognizable email address and real name as your sender. There shouldn’t be any spammy words in your subject lines.
  3. Send emails at a consistent cadence.
  4. Feature mobile-friendly and consistent designs.
  5. Include plain-text/HTML versions of every single email.
  6. Avoid shortening URLs while linking externally.
  7. Segment your email list.
  8. Add simplicity to the unsubscribing process.

Undoubtedly, sending a successful email campaign needs plenty of effort. Yet, while considering email marketing, we understand that it is rapidly becoming the topmost way to drive revenue, and it makes everything worth it.

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