Email deliverability: 18 tips to ensure your emails are delivered to inboxes (not spam folders)

Every creator’s worst nightmare is finding out their newsletters are being delivered to the spam folder.

Luckily, there are ways to improve your sender reputation and influence your email deliverability to keep your emails out of spam and into your subscribers’ inboxes—where they belong.

What is email deliverability, and how is it defined?

Email deliverability is the ability for an email to get delivered to the recipient’s inbox without being blocked or marked as spam.

But don’t mistake deliverability with delivery. These two terms are often used interchangeably but have distinct meanings.

Delivery rate refers to the number of emails successfully delivered divided by the number of emails sent, whether they land in the inbox or other folders, like spam.

Once a message has been successfully delivered, it’s in the hands of a mailbox provider (MBP), for example, Gmail, Hotmail, or Yahoo, to place the email in the inbox, spam folder, or trash.

Each MBP has unique algorithms and the freedom to handle an email however they want.

On the other hand, deliverability measures your messages’ inbox placement.

All senders aim to have good deliverability, which means having their messages end up in the inbox rather than other places like spam.

With delivery, it’s easy to measure performance: A message is delivered, or it isn’t.

Unfortunately, when it comes to deliverability, measuring success isn’t as straightforward.

MBPs don’t tell senders what happens to messages after being delivered. Only the mailbox provider and the recipient knows where the message was placed after delivery.

That’s why, as creators, you focus on metrics like open rates, click rates, and conversion rates to indicate the performance of your email’s deliverability.

Kit’s (and other email service provider’s) role in email deliverability

Kit provides and manages digital identifiers like IP addresses, sending domains, and link-tracking domains for your messages and acts as an email service provider (ESP). We have a team of experts to ensure all of these identifiers have a healthy reputation so MBPs place your message in your subscribers’ inboxes.

However, not all email service providers are as diligent with email deliverability.

As a creator, you need to be careful with whom you use for your ESP. Otherwise, you risk your emails going to spam.

One simple way to measure the health of these digital identifiers is to look at your ESP’s delivery rate. Kit’s system-wide delivery rate is 99%, which means 99% of the emails our creators send are delivered.

Along with keeping the reputation of our infrastructure healthy, Kit also:

• Ensures messages are sent at the proper rate for each mailbox provider
• Stays on top of industry news and trends to adapt to any changes
• Maintains relationships in the email industry so we can advocate for our customers
• Stops spammers from using our platform maliciously
• Manages feedback loops to ensure subscribers who complain are inactive from your list and let you know if your complaint rate becomes elevated
• Handles bounces to ensure that invalid addresses are inactive on your list and don’t harm your reputation

Sender reputation: Your role in deliverability

While Kit helps your messages get through the door, most factors that influence deliverability are in the hands of the sender, a.k.a. you.

The top factors are:

• List collection
• List health
• Sending frequency
• Content

To have a good sender reputation, you want to send as many positive signals to MBPs as possible and minimize any negative signals.

These signals are sent by the way your subscribers interact with your messages. The chart below indicates which subscriber actions are positive, neutral, or negative.

Things like opens, replies, clicks, and adds to the address book are positive signals, while things like unopens, deletes, opt-outs, and marking emails as spam are negative.

18 best practices on how to improve your sender reputation + email deliverability

1. Choose a reputable email service provider

Choosing a reputable email service provider to handle your email marketing is your strongest defense against poor email deliverability.

Reputable ESPs have teams of experts who work tirelessly to ensure their deliverability remains high.

When looking for a reliable ESP, be cautious if they want you to get a dedicated IP.

Here’s why.

When you send emails, you need to send them from an IP (as we mentioned earlier).

Some ESPs make you buy and manage your own IP.

The idea behind individual IPs is that one bad sender won’t wreck the IP reputation of everyone else since everybody has separate IPs.

However, IP management can be costly and time-consuming.

At Kit, we don’t believe the responsibility (or cost) of IP management should fall on our customers’ shoulders. We manage the IP for you, meaning you won’t need to pay anything extra on top of the price listed for our plans.

We also take time to make sure our IP reputation is in tip-top shape, and you don’t need to worry about a poor IP reputation.

2. Make sure your emails pass authentication

The easiest way to check if your emails pass authentication is to send yourself a test email. f you get your email without any warning messages, it likely passes authentication.

Email authentication is a set of protocols to prevent email forgery and spoofing attempts. It includes things like:

1. DomainKeys Identified Mail (DKIM): DKIM was designed to prevent domain spoofing or someone pretending to send from your email domain. DKIM uses cryptographic authentication, which means the records we generate will be unique to you and your domain.
2. Sender Policy Framework (SPF): SPF was specifically created to protect against sender address forgery (spammers pretending to send emails as you). An SPF record in your DNS Settings gives email providers something to check to make sure the emails are really coming from you.
3. Domain-Based Message Authentication, Reporting and Conformance (DMARC): A security measure you add to your domain to prevent spammers from spoofing your domain.

Kit authenticates DKIM and SPF for you, while DMARC authentication is managed within your domain host settings.

Keep in mind that you don’t need to enable DMARC authentication to send emails.

The only time you’ll want to test your emails is when your messages land in spam or aren’t being delivered.

If you do have DMARC enabled, you’ll need to set up a verified sending domain so your emails can pass DMARC authentication and be delivered successfully.

3. Check for a valid MX record

An MX record is a Domain Name Server (DNS) record that tells email services which mail server is in charge of receiving and handling emails for a particular domain.

Think of it like a signpost that guides emails to the right place, ensuring they reach the correct mail server associated with the domain they’re being sent to.

You can check your MX record here. If you don’t have an MX record, you’ll see this error:

To create an MX record, you must contact your domain host.

4. Only send emails to people who have consented

While buying a big email list may sound tempting, doing so can harm your sender and email reputation.

First off, you can’t be sure that everyone on the list gave their permission to be on the email list, which can violate laws like CAN-SPAM and open you up to hefty fines.

Secondly, if you buy an email list, many of the email subscribers will immediately mark you as spam the minute your first email newsletter hits their inbox. When this happens, it dramatically decreases your email deliverability rates and can damage your domain reputation.

Lastly, Internet Service Providers (ISPs) place fake email accounts that look like real emails around the web to identify people who buy email lists. These are called spam traps.

If you buy an email list that contains a spam trap email, the moment you send something to that email, you could be added to a blocklist.

You can check if you’re on any blocklists here.

If all the checkmarks are green, like the photo above, you’re not on any mainstream blocklists.

If you’re on a blocklist and don’t think you should be, you can reach out to the blocklist agency and ask to be delisted.

5. Create lead magnets that attract the right subscribers

Some lead magnets are better than others to grow an email list.

For example, giveaways might attract lots of new subscribers, but if the giveaway is too general (like a giftcard to a popular department store), the people who sign up are unlikely to be your target audience.

After the giveaway ends, they’ll ignore your emails or, worse, mark you as spam.

Instead, create lead magnets that attract a targeted group of people. Artist Angela Fehr’s lead magnet isn’t just for artists; it’s for watercolor painters who are stuck in a rut.

6. Use double opt-in

To limit fake email addresses and keep a clean email list, use a double opt-in.

Here’s how it works.

When someone signs up for your list, the potential subscriber is shown a message instructing them to confirm their email address. At the same time, an email is automatically sent to them with a confirmation link.

Only after they confirm their email will they be added to your email list.

Double-opt in ensures every email on your list is real.

It also prevents list bombing. List bombing is when a bot or a person uses someone else’s email (or a fake one) to sign up for your lead magnet.

With double opt-in, you can ensure only real emails (and people who want to sign up) end up on your list.

7. Use a ‘Thank You’ page to stay out of spam and promotion folders

Sometimes emails to new subscribers end up in spam and promotion folders for reasons beyond your control.

To help ensure your emails end up in the right place, use a thank you page that instructs people to move your emails into their inbox if necessary.

8. Segment your email list

Segmenting your list is another way to ensure high deliverability.

Here’s why.

Let’s say you’re an artist who sells paintings and also teaches art classes.

Some people who sign up for your list might only want info on your classes. Others might only want to hear about the paintings you sell, and some might want a bit of both.

The easiest way to ensure your subscribers get the emails they want—and don’t mark you as spam for sending stuff they aren’t interested in—is by segmenting your list.

One quick way to segment your list is to let users self-select which types of content they’re most interested in right on your sign-up form.

9. Write compelling and engaging subject lines

You want your email subject lines to stand out in your subscriber’s inbox without resorting to clickbait.

Misleading subject lines confuse readers and reduce their trust in you.

If this happens consistently, they’ll most likely unsubscribe, but they may also report you as spam. If enough subscribers do this, your email deliverability rates can take a hit.

Here are a few subject lines that do a good job of telling the reader exactly what’s inside:

Regularly check your open rates to see how your subject lines perform. If your open rates start decreasing, take action by A/B testing different subject line variations until you find the messaging that works.

10. Send from your own domain

Be sure you aren’t sending from a free domain such as gmail.com, icloud.com, or yahoo.com. Doing so causes messages to either bounce or go to spam.

Instead, use your own domain, like creator Susanna Gebauer does.

11. Send quality and relevant content

Crafting engaging, informative, and valuable emails not only makes your subscribers happy, but it also contributes to better deliverability rates.

We’ve put together an entire post compiling excellent newsletter examples to give you inspiration, but let’s go over some best practices to help you get started.

Personalize your emails

Similarly to frequency, personalization is key.

Make sure your content provides value to your subscribers by learning about who they are and what they like. Even better, segment your list to send out highly-relevant and personalized content to each person.

Create plain-text emails

Plain text emails result in faster load times and have better readability.

Here’s a plain text email from Susanna Gebauer. It’s easy to read, and there’s no fancy design to distract the reader from her main point.

Add alt text when using images

Everyone loves a beautiful picture or graphic, and they often convey a thought or point quicker than text.

But when you use images in your email, pair them with descriptive alt text. Alt text is useful if your recipient uses a screen reader or if the image doesn’t load properly. With alt text, you ensure everybody gets the same information from your emails, even if your images don’t load.

Using Kit, you can add unique alt text for each image within your newsletters.

Aim for at least 500 characters

Too little text can be a red flag for spam filters.

Include at least 500 characters, which is typically less than 100 words. Here’s what 500 characters looks like:

Don’t use link shorteners

Because link shorteners are often by spammers to cloak malicious links they can raise red flags for spam filters.

Transparency is key for good deliverability. When adding a link to your emails, link directly to the website rather than use a link shortener.

Image-to-text ratio

Your email should have enough text so that if images fail to load, you can still communicate your main point.

Artist Dianuh Aerin’s email has two images that link to her YouTube videos. Dianuh smartly includes a link to her YouTube channel in her email’s copy in case the images don’t load.

Avoid gimmicks

Avoid quick tricks to boost engagement.

While you might see a temporary boost in open rates from a subject line that says “Re: Your Order #2095642”, you’ll lose subscribers’ trust, and your audience will likely mark you as spam.

Instead, focus on providing consistent value over time.

Don’t use no-reply emails

Spam filters often filter out emails from no-reply emails. They also provide a poor user experience for your readers.

Not to mention, replies from your subscribers can help your email deliverability, so there’s no reason to prevent them.

Spell-check

Emails rife with spelling and grammar errors often indicate low-quality content and can make subscribers mark you as spam or unsubscribe.

Don’t fret about the occasional misspelled word (we all make mistakes!). Instead, try to keep your emails free from spelling and grammar errors as best you can.

Make it mobile-friendly

A large chunk of your subscribers will open your emails on their phones, so you must ensure every email you send looks great on all devices.

Here are some tips:

• Use a larger font for mobile
• Include large clickable buttons
• Make use of white space and short paragraphs
• Keep your emails concise to avoid scroll-fatigue

Copywriter Charlene Burke’s mobile version of her email has a nice clickable button with plenty of whitespace.

You can check if your emails are mobile-friendly by sending a test email to yourself and opening it on your phone.

Keep it light

Be sure your message size is less than 100KB. It might get clipped if it’s too large, which is when mailbox providers shorten your email.

As a result, your recipient can’t read your full email, and the open tracking pixels won’t load, making your open rates uncharacteristically low.

To test the size of your email, send the email to yourself, download it, then look at the file size of that download.

12. Include a clear call-to-action (CTA)

A CTA helps drive clicks and engagement within your emails, improving sender reputation and email deliverability.

For high engagement, make your CTA clear so your subscribers know what to do, otherwise, you risk them leaving your emails without clicking anything.

13. Give an easy-to-find unsubscribe link

While unsubscribes may initially seem negative, they’re a good thing.

Why spend time and money nurturing an email subscriber who doesn’t want to read your email content?

It’s better to cater your emails to people who are loyal subscribers of your brand.

To keep a clean and healthy list, include an easy-to-find one-click unsubscribe link at the bottom of your emails, like coach Kate Hesse does.

This is also required by law due to the CAN-SPAM Act, which states that email senders must allow recipients to opt out of receiving emails at any time.

14. Review why people unsubscribe

To keep your email deliverability high, find out why people unsubscribe by using unsubscribe surveys.

Dig into your survey responses to see if there are any glaring reasons people unsubscribe (like they find your emails inappropriate). Use this feedback to tailor your email marketing strategy and keep subscribers happy.

15. Be consistent with your email delivery schedule

If you typically send one email every two weeks and suddenly ramp up to two emails per day during a product launch, you may see an increase in unsubscribes and complaints, which can hurt your deliverability.

To combat this, stick to a consistent schedule and notify subscribers if you plan to increase the number of emails you send.

Tip: Make sure you send your emails at the right time. Get your emails into your subscribers’ inboxes when they’re likely online to increase the chance they open—and read—your newsletter.

16. Clean your list regularly

There are two types of subscribers to keep an eye on: cold subscribers and bounces.

While cold subscribers and bounces can hurt your deliverability, they’re easy to manage.

Here’s how.

Cold subscribers

Cold subscribers are people who aren’t opening your emails. And when a large chunk of people don’t open your emails, it hurts your deliverability.

One way to eliminate people who aren’t opening your emails is by pruning your list of cold subscribers.

Start by locating your cold subscribers in Kit.

Next, select all of them using the checkboxes and tag them with a unique tag.

Then, use our helpful email automation to try and re-engage those cold subscribers before removing them from your list.

Grab the Cold Subscriber Re-engagement template here

Hard and soft bounces

Hard bounces are emails that don’t exist. No matter how many emails you send them, they always bounce, and as we mentioned earlier, a list with lots of hard bounces can hurt your deliverability.

At Kit, we automatically categorize any email addresses that hard bounce as a “bounced subscriber”.

Bounced subscribers don’t receive any future emails, so you don’t need to worry about them. If your ESP doesn’t remove hard bounces for you, you’ll have to remove them manually.

Soft bounces are slightly different.

A soft bounce occurs for a temporary issue—like a full mailbox. Soft bounces aren’t generally a cause for concern since they’re temporary. If the email turns into a hard bounce, Kit will automatically move them out of your active subscribers so they don’t hurt your deliverability.

Remember: The more cold subscribers and hard bounces you have, the higher the chance you’ll see open rates decrease and spam filtering increase.

17. Test and optimize your emails

To send out the best emails possible, use each email you send as a learning experience.

A/B test subject lines and try new things to see what sticks with your audience.

When you craft highly-enjoyable content, more people will open your emails, and your email deliverability and sender reputation will remain high.

18. Monitor your email reputation metrics

If you adhere to the best practices we’ve covered above, your deliverability rates should be healthy and penalty-free.

As you put these into practice, keep an eye on your email marketing metrics to ensure you give your subscribers the best and most relevant content. Because as we’ve learned, the higher the engagement from your subscribers, the higher your email deliverability will be.

Let’s dig into a few relevant metrics you can monitor.

Open rate

Increasing your open rate is one way to improve your sender reputation (and deliverability).

Let’s take a look at some open rates against sender reputation:

However, open rates and sender reputation don’t always work hand-in-hand and the relationship between the two isn’t always straightforward.

For example, you could have a great sender reputation but have an authentication failure. This would lead to low open rates despite being a reputable sender.

Also, open rates are not always accurate. To understand why, let’s quickly review how ESPs track open rates.

Every email you send (via your ESP) contains a tracking pixel. When that pixel loads, the “open” is triggered.

But a few issues with tracking pixels can distort your open rates. For example, Apple’s Mail Protection Privacy (MPP) automatically loads pixels before users open the email. This inflates your open rates, making them inaccurate.

Regardless, a sudden dip in open rates can still alert you to potential issues with your deliverability.

Click rate

When analyzing click rate, look for any major and sudden drops. A drop in clicks can signal deliverability issues or issues within your content.

One way to keep your click rate high is to have a clear CTA on each email you send.

Spam report or complaint rate

A complaint is when a subscriber marks your message as spam. A complaint rate of 0.1% is considered normal and isn’t a cause for concern. (Think of this as one out of 1,000 subscribers marking your message as spam.)

However, a complaint rate greater than 0.1% can damage your sender reputation. If your complaint rate is greater than 0.1%, consider cleaning your list, segmenting it, and adjusting your email marketing strategy.

Keep in mind it’s normal to receive some complaints, but an elevated complaint rate can cause your sender reputation to drop significantly.

Tools to test your email deliverability

We recommend a few tools to find out where you currently stand with your deliverability and diagnose what issues you need to fix.

On the most basic level, MailTester and GlockApps test against Spam Assassin (an open-source anti-spam platform) to tell you the health of your email deliverability.

Here are a few more advanced deliverability tools:

ListGoal

If you want a more comprehensive email marketing dashboard, check out ListGoal.

It’s a web browser extension available for Chrome and Firefox that offers a free lifetime account to anyone who signs up.

List Goal will:

• Keep you updated on the overall health of your email list
• Track your subscriber count
• Grow your email list to attract more quality leads

List Goal also integrates with Kit. Simply sign up with your email and connect the two through your Kit API Key.

Validity

With advanced data and analytic capabilities, email deliverability solution tools like Validity can help you determine where deliverability rates are going awry and how to fix them.

Sender Score

Sender Score measures the effectiveness of your reputation as an email marketer. Simply add your domain or IP address to their search bar to access data that helps you improve your email and domain reputation.

Talos Intelligence

Talos Intelligence is an in-depth tool that allows you to monitor your IP address and domain reputation while discovering potential threats to your domain.

You can also track your email and spam data over time to see if there are any trends you need to be aware of.

Ready to improve (and maintain) your sender + email reputation?

While there are plenty of strategies you can implement to maintain a high deliverability, a lot depends on your ESP.

If you’re unhappy with the email deliverability at your current email provider, or if you are looking for an email marketing platform you can trust, we’d love for you to try Kit.

Try Kit for free to see how many more emails will make it into your subscriber’s inboxes.