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How to Rock Your Email Deliverability (2024 Update)

Find out what you can do to improve your email deliverability – from what metrics to track, and tricks on optimizing your email strategy, to a few handy tools.

Octavia Drexler
By Octavia Drexler

Updated February 21, 2024.


Imagine all of the owls in Harry Potter got lost and sent to Mordor instead. Likely, the story would've been slightly different – no more letters from Hogwarts, no more invitations to attend the school when you turn 11, and no more owls delivering messages from Dumbledore. Instead, the Dark Lord Sauron would have a whole army of magical flying creatures at his command.

If you are confused by the fantasy world mishmash, you're right to be. But that's only because we're going to do a very smart segue here: Harry Potter owls, lost in Mordor, is a lot like email deliverability: misdirected messages, unreliable carriers, and lots of confusion.

Handling your email deliverability is important for all your email marketing efforts. Without it, you can craft the best messages, create the prettiest designs, and build the most engaging campaigns, but none of it will matter if your emails never make it to the inbox.

How to make sure your emails get to where they need to go? That's what this post is all about.



What is email deliverability?

Email deliverability is the ability of an email to arrive in the recipient's email inbox. It's often measured by the percentage of emails the email service provider accepts.

Email marketers track email deliverability metrics such as bounce rates (hard and soft), delivery rates, spam rates, and engagement rates. Together, they reflect an organization's ability to send and deliver email communications to audiences.

Email delivery rate is essential because if you ignore it, you risk not reaching your intended audience (or at least not in full). You can send as many promotional emails as you like, but if email providers like Gmail or Apple don’t accept them as legitimate emails and place them in users’ inboxes, it’s futile.

By implementing a variety of coding, sending, messaging, and authentication best practices, organizations can maximize their deliverability and inbox rates.

Deliverability vs delivery

These two terms are sometimes used interchangeably and can be quite confusing, so let's break them down:

  • Delivery, or inbox delivery, refers to a sender’s ability to have their messages both delivered and placed in the inbox.
  • Deliverability is simply having a server accept (or not reject) a message.

Servers can reject emails, IT teams can set up whitelisting or keyword quarantine rules, user profiles can determine folder placement. There are many steps and checks between server deliverability and inbox delivery. However, both deliverability and delivery are critical measures for those interested in improving their email marketing.



Why is email deliverability important?

Email deliverability measures how many of your contacts receive your emails. And without high delivery rates, your marketing emails will not be read.

Take a look in your junk folders. You’ll find hundreds or thousands of spam messages that were auto-filtered out of your email inbox. When organizations are careless with their sending practices, their emails end up in the spam folder.

The result is low click rates, low engagement, and low traffic to destination URLs. The worst part is deliverability often never crosses the marketing manager's mind until a new expert comes in or one is hired to troubleshoot and analyze key metrics.

What is the average email deliverability rate?

The average rate for the bulk of commercial senders is between 83% and 89%. This means 95% of emails are not rejected by receiving servers.

Do the same 83-89% of all emails also arrive in user inboxes? Probably not.

Generally, promotional emails should have lower deliverability performance than transactional messages. The reason is that transactional emails have a much higher engagement rate than promotional emails.

Promotional messages “should'' have lower deliverability, but it gets murky in a few situations (e.g. sharing IPs between senders) so we won’t dig too deep into the weeds here. Transactional messages have higher engagement levels, leading to higher deliverability and inbox rates.



How to test email deliverability

There is no singular test to completely assess your ability to have emails delivered, but there are various email tools you can use. Combine the findings of these tools, and you can gain insights to better identify opportunities for improvement.

Here are a few tools for assessing deliverability and inbox delivery rates:

Sender authentication tools There are different methods for email senders to authenticate themselves. The main benefit of authentication is that receiving servers look for ways in which senders identify themselves to determine whether to accept a message (deliverability) and then whether to place it into the junk or inbox folder (inbox delivery).

Many of these tools are free and will provide insights into what’s missing and which opportunities are outstanding. Examples include SenderScore, a free tool to check how viable you are as a sender, and SendPost, an advanced sender optimization tool that starts at $7/month.

Email coding and rendering tools You can find paid and free online tools to evaluate an email message and determine its compliance with coding standards. It’s common for a marketing team to focus their designs on the tools or platforms they use. Be sure to ensure your messages render correctly in all browsers and email clients. Also, test your email marketing flows and programs as often as you make changes to them.

For instance, Mailtrap (free for 100 email tests/month) and Mailosaur (starting at $9/month) help web developers identify deliverability issues in coding and fix them as easily as possible.

Email SPAM check tools Using keyword lists and code verification methods, some tools can “read” your message to help you determine its deliverability score. Many of these tools are free and offer suggestions on eliminating repetition and spammy language, as well as filter trigger words.

If you want to test your emails for SPAM triggers before sending them, you can use Mailmeteor’s Spam Checker or Mailgenius. Both are free. One tests for email content, and the other, your sender email.

Deliverability and delivery service providers There are a handful of partners that specialize in email deliverability. These are typically monthly services where organizations have access to a platform with intricate metrics and some type of success manager to work with them on weekly or monthly intervals. Keep in mind that they tend to be costly!

Internal deliverability metrics analysis and optimization Testing deliverability is about optimizing engagement metrics and matching campaigns with targeted audiences. It’s important to develop internal reporting and dashboards to help monitor past, current, and future performance.

What is an email bounce?

A bounce is an email message that is rejected by the server and returned to the sender with an accompanying note. There are two categories of email bounces: soft bounces and hard bounces.



What is a soft bounce?

Soft bounces are events caused by temporary issues, such as a full mailbox or an overloaded email server. If you notice soft bounces, try this email list hygiene trick: email these addresses with as relevant content as possible up to four times in 30 days. If all emails get rejected, permanently remove this user or have them quarantined for 3 months, then try another four times in 30 days.

What is a hard bounce?

Hard bounces are caused by permanent problems, such as an invalid email address or a manual server blockage. If you notice hard bounces, remove the addresses immediately and perform quarterly checks to recover emails by manually cleaning them.

The most important part of bounce management is ensuring your platforms and tools are respecting bounce management best practices. The majority of tools have these features built-in in order to handle different types of message rejection for you.

Top factors influencing email deliverability and inbox rates

There’s a lot that goes into email deliverability and inbox rates, including

Sender and IP reputation

A sender’s IP reputation is based on the messages sent from it. Most small and medium-sized businesses are in a shared IP environment, rather than a dedicated one. Sharing IPs with other senders is a standard way to pool resources and save money. Plus, dedicated environments are typically reserved for high-volume senders. In short, your reputation is shared, which is why most senders have to respect the strict sending rules of their service providers.

Email authentication

Email authentication is similar to a return address on a postage envelope. It involves the setup of DNS records to confirm a sender’s identity. The benefit of implementing email authentication is improved deliverability and inbox rates. Failure to authenticate as a sender will make ESPs suspect you of email spoofing or phishing; in other words, you’ll be flagged as a (potential) spammer. The most common ways to authenticate nowadays are via DKIM, SPF, and DMARC.

Message contents

The promotional or transitional message itself must contain content that will not trigger any spam flags or email deliverability issues. There are several best practices to follow here, ranging from coding accessibility and email size to redirection protocols and spammy messaging.

Message engagement (opens, clicks)

Engagement is a major contributor to deliverability and inbox delivery rates. ESPs regularly use data on open and click activity to assess content relevance and audience interaction rates. Organizations should always be optimizing for engagement rates to ensure their emails are delivered as intended.

For example, when an anniversary email fails to generate ample engagement, it’s time to disable or optimize. When a welcome email series produces little traffic, rebuilding and re-engaging is time.



How to get out of the dreaded spam folder

What do you do if your emails reach the spam folder?

There are two main ways your emails can land in the forsaken Spam folder:

Spam complaints

Spam complaints are a major red flag for email providers. If your unsubscribe rate is high, you’ll see an increase in spam complaints, too. That’s why it’s important to provide a simple and easy way for users to unsubscribe from your emails, and to honor these requests promptly.

Additionally, make sure your subject lines and content are aligned (don't use misleading, or click-baity subject lines), and avoid using spammy language. This is important for any professional-level email program, even beyond deliverability concerns.

Spam traps

Spam traps are email addresses that have been created for the sole purpose of catching spammers. These addresses are often published online in places where bots and spammers can scrape them, or they can result from old or abandoned email accounts.

If your list is full of spam traps, it's a clear indication that you've acquired those emails dishonestly, and your sender score will be lowered. Eventually, you'll be marked as a spammer by email providers. To avoid this, always use ethical and legitimate methods of collecting email addresses, such as double opt-in and regularly cleaning your list.

Email blacklisting: what you need to know

Email blacklisting is slightly different than spam filtering. While spam score filters check the content of your emails to determine if they are spam or not, blacklists keep a list of IP addresses or domains that have been flagged for sending excessive amounts of spam.

What happens when emails are blacklisted

If your IP address or domain ends up on a blacklist, this can severely impact your email deliverability as many email providers will block emails from these senders. This can lead to a significant decrease in open and click-through rates, affecting your overall email performance.

How to avoid being blacklisted

To avoid being blacklisted, make sure to add these to your list of email best practices and guidelines:

  • Regularly clean your email list
  • Use secure authentication methods
  • Provide easy opt-out options for users
  • Monitor your sender reputation

Psst! Working with an email expert can help you preempt and address all these issues, so you can focus on creating and sending effective email campaigns. Contact Mayple, and we'll match you with one of our vetted email marketing experts in under 72 hours!



20 tips to improve your email deliverability rate

If your email deliverability rate isn’t quite where it should be, don't worry! Anyone who has run an email marketing campaign will tell you that it happens all the time. The important thing is that you do what you can to improve it. Here are 20 tips you can start implementing right now to get positive results:

Use free tools

There are many free tools to measure email template rendering, message and copy, sending and delivery, and more. Get familiar with these tools, save them to your favorites, and build your resource list for current and future needs. Our list of the best email marketing tools is a great place to start.

Monitor key metrics

If possible, monitor deliverability metrics such as bounce rates and breakdown by bounce type. It’s easy to pinpoint opportunities and audience issues by tracking issues and finding patterns. Email marketers will tell you to look beyond open and click rates, and get into the weeds to optimize for inbox rates truly.

Keep an eye on your neighbors

Some email platforms are less careful than others when managing their clients. An IP may be temporarily hurt because one of the many different senders has failed to respect rules or best practices. Online tools can help identify the parties in an IP-sharing pool.

Follow data, privacy, and spam laws

Each country, and sometimes each region, can have its own set of rules and guidelines for managing consent, privacy, and user data. Stay up to date and integrate the latest requirements to avoid headaches. If you're finding it too tricky to interpret some legislation, get advice from both a legal expert and an email marketing consultant for a balanced perspective.



Make emails accessible

This surprises many: emails can be coded to accommodate individuals with impairments. When we build our templates without these accessibility options, we're ignoring a valuable audience while telling ESPs that we cut corners on our user experiences. Adding accessibility elements to templates is surprisingly easy.

Text-only versions

Text-only versions of email messages are still important, albeit for a small segment of your audience. Similar to adding accessibility features, this is another best practice that’s easy to adopt. Further, the majority of tools and marketing platforms will automatically build text-only email versions for you. Spend a few minutes to ensure they’re formatted correctly.

Subscription permission reminder

Keep deliverability high by minimizing spam complaints. One effective way to do this is to ask audience members how they came about your message, and that they subscribed to receive it. It’s a gentle disclaimer that shows you respect their wishes, and that they can change their subscription options at any time.

User preference management

Another method for managing spam complaints (and unsubscribes) is to give users more tools to manage the communications and notifications you send them. Allow your leads and customers to dictate their correspondence frequency and content, especially if you tend to send a high volume of emails. This helps minimize spam complaints while minimizing audience attrition and unsubscription.

The easiest way to do this is to add that unsubscribe link at the bottom of all your emails. You could also consider using a double opt-in to make sure new arrivals to your email list actually want to be there.

Understand your environment

Learn whether you send from a shared or dedicated environment. It’s common for marketers to mistakenly apply dedicated IP best practices to a shared environment. Each environment has different and often opposite requirements to adopt.

Practice list hygiene

Whether manually or using an automated tool, keep a clean email list by removing inactive users, unsubscribed users, and those who have filed a spam complaint. Poor list hygiene is one of the quickest ways to damage email deliverability and reduce inbox delivery rates.

email hygiene list checklist


Don’t sacrifice high engagers

Organizations often push hard for acquisition in the form of communication with inactive, disengaged audience members. Care not to sacrifice the high engagers (those that click and spend) in an attempt to maximize reach to a bad audience. Engagement is a key factor in maximizing deliverability; sending too many unopened emails can have a (hopefully temporary) negative impact on a sender’s ability to then deliver to more engaged email subscribers.

Match sending and destination URLs

External links from emails should be pointed to the same domain or TLD that the message is sent from. Many tools and platforms will “auto-track” all email links by wrapping them in a redirection and allowing marketers to append special tracking parameters. Avoid unnecessary flags by linking internally only.

Avoid list buying

Tempting as it is, buying lists is nowhere near as useful as it once was. For starters, it's illegal in many locales. On top of that, integrating an external list is likely diluting your list with unengaged subscribers – or worse, fake email addresses – which messes with your engagement rate, as well. Adding thousands of new audience members who fail to click or open will be detrimental to database management and growth optimization efforts.

Exercise good bounce management practices

Properly manage audience hygiene between sends to maintain a strong sender reputation and hit the most inboxes. Avoid delaying the removal of bounces or unsubscribes, otherwise suffer the swift and often undetectable punishment of a high spam complaint rate. As mentioned above, deliverability metrics are rarely monitored so ensure good habits are being practiced consistently.

Avoid spammy words and messaging

We get it: if you're a low-volume sender, you need all the help you can get to maximize inbox delivery rates. But uppercase text and excessive use of exclamation points make you look desperate! Tone down your email copy and focus instead on what value you can provide to your audience.



Include media fall-back options

Several technologies like video and AMP can be integrated into email messages, but none of them have widespread compatibility. This means that marketers need to integrate new technologies, as well as fallback options for users who are unable to experience them as intended.

Check your spelling

Poor spelling is a quick way to get dinged on deliverability. Ensure that a strong QA, review, and editing process is involved with all email content. This includes template elements like header and footer. Spelling mistakes in your fine print is quite an unnecessary nuisance!

Strategic sender name and from address

Sender from name and email can be manipulated to convey a personal touch or a less-than-generic tone. Include these two parameters in all testing. It is surprisingly common to have an old process running in the background with incorrect identification leading to an email address that is invalid or unchecked.

Test template rendering

Use free or paid tools to analyze the coding and rendering of the templates in your campaigns and programs. Sadly, not enough businesses understand how to optimize and account for various email clients, platforms, devices, and resolutions. A good tool will help validate email performance across all major software versions.

Develop QA process

Sending promotional and transactional messages requires a strategic approach where you regularly assess your results and make changes accordingly. Invest time into developing a process or protocol for creating, integrating, testing, sending, and measuring performance. Email marketing lends itself to errors and bugs, and it’s important to set ourselves up for success with every email campaign.



Best email deliverability testing tools

Luckily, there are quite a few tools you can use to improve your email deliverability:


MailTester is an email verification and deliverability tool with single and list verification features, as well as inbox testing features. It integrates with popular email marketing tools like Mailchimp, AWeber, HubSpot, and more.

They have two pricing models you can choose from:

  • Pay-as-you-go – a credit-based plan that costs $19 for 5,000 emails, $29 for 10,000 emails, etc.
  • Subscription – four different pricing tiers that range from $39/month to $299/ month.


Mailtrap is a robust tool for testing email deliverability. It allows safe testing of email notifications without spamming real customers. Mailtrap provides a fake SMTP server for your development team, ensuring no test emails reach real users. This tool offers a centralized platform to view and inspect emails online and debug and adjust HTML, text, and other properties. It supports multiple inboxes, team collaboration, BCC testing, and popular framework integrations.

Mailtrap has six pricing tiers, starting with free, or $14.99/month, and a range of other packages that go as high as $399.99/month. Each plan increases incrementally according to the number of test emails per month, desired sending limits, inboxes, team members, and so on.


Spamchek specializes in providing robust email security solutions. Their primary services include a spam and virus filter, which effectively blocks over 90% of all spam emails and prevents up to 10% of email viruses from reaching your mail server. Spamchek also offers an email archiving service.


MxToolBox is a comprehensive online platform that offers various tools for analyzing, monitoring, and enhancing email and web security. The platform's primary offerings include MX Lookup, which lists MX records for a domain in priority order. It also provides diagnostics that connect to the mail server, verify reverse DNS records, perform a simple Open Relay check, and measure response time performance.

With MxToolBox, you can get real-time insight into email deliverability, allowing users to understand how recipients perceive their emails through feedback on complaints, unsubscribes, failures, and more.

The three pricing tiers for MxToolBox are

  • Free – which covers one domain and weekly monitoring
  • $129/month – for five domains and advanced features
  • $399/month – for five domains, advanced features including SPF flattening and advanced email deliverability threat tools

Warmup Inbox

Warmup Inbox is an online platform designed to help improve your email sender reputation and deliverability. It does this by automating the process of sending and interacting with emails from your account, ״warming up" your inbox. This can be particularly useful if you're using a new email address or domain that hasn't yet established a reputation with email providers. Warmup Inbox offers different pricing plans based on the number of inboxes you need to warm up.

This tool is available in three pricing tiers,

  • $19/month (warm up to 75 emails per day)
  • $49/month (warm up to 250 emails per day)
  • $99/month (warm up to 1,000 emails per day)

Email deliverability: not just a number in a spreadsheet

The world is waking up to the importance of data privacy. Simple things, like including an unsubscribe link in your emails, ensuring you use a 3rd party mail system to test your emails, and steering clear of spammy keywords and tactics, can do a lot for your mail deliverability. 

Additionally, using a double opt-in process that gets users' explicit permission to be emailed (or making sure single opt-in and double opt-in lists are separated) improves your email deliverability from the get-go to reach more inboxes. 

On top of everything, regularly remove unengaged subscribers and invalid addresses to keep a clean list of subscribers and be perceived as a responsible sender. At the end of the day, having a very large email list full of inactive subscribers serves no one. Having engaged subscribers, however, can make all the difference.

You want to be perceived as a legitimate sender. Having poor sender reputation ties into your brand, how customers perceive you, how many active subscribers you have, your domain reputation, and, in the end, how your entire business sells and grows. 

Your email deliverability rate is a metric you want to improve, as it directly correlates with your inbox placement rate (i.e. the percentage of emails accepted in users' inboxes, not their Spam folders). No matter the mailbox providers or email clients (Gmail, Outlook, Apple Mail), ensure your messages get through the spam traps, and into inboxes.

Need help making sure your emails reach their destination every time? Find the right Mayple-vetted email marketing consultant experienced within your field in under three days. Let's get cracking!