18 effective strategies to improve email deliverability in 2025

But you can’t ignore it. Improving your deliverability will have a big impact on your campaigns, increasing opens, clicks, leads and even sales. 

What’s more, there are plenty of simple steps you can take to improve your deliverability. And many of these are email marketing best practices that will help your campaigns far beyond the impact they have on deliverability.  

Read on to learn 18 email marketing deliverability best practices to help direct your emails straight to the inbox.

Email deliverability is the ability of your emails to reach your subscribers’ inboxes rather than bouncing or reaching the junk folder. 

Good deliverability is essential to effective email marketing because messages that go to spam don’t get read. When you improve deliverability, more people will see your emails, your engagement metrics will improve, and your email campaigns will become more effective.

Key factors that affect email deliverability

There are 4 key factors that impact your email deliverability. All the deliverability-improving strategies in this article focus on these points. 

1. Technical optimization and authentication

The right technical setup gives you the base you need to reach the inbox. It helps you build a reputation as a legitimate sender, which means your messages are less likely to be marked as spam. 

Your email service provider will take care of some technical details, such as keeping your domain warm. It will also help with others, like domain authentication. That’s why it’s so important to choose a reputable tool with a good reputation for deliverability. 

2. List hygiene and subscriber management

To keep your deliverability high, pack your list with interested subscribers who opted in to receive your content. These people are more likely to engage with your emails, which is a sign to inbox providers that you send quality content. You’re also less likely to send to inactive accounts that people no longer check.

When you keep your list up-to-date and clean, you're also far less likely to send to spam traps. These are email addresses that have been repurposed by ISPs to catch spammers. If you send to one of these accounts, your sender reputation will suffer.

3. Content and engagement strategies

Good email content leads to high engagement, which leads to good deliverability. Plus, inbox filters will often look at your content for signs of spam—if your content fails these checks, you’re more likely to land in the junk email folder. 

4. Sending practices and monitoring

When you send emails consistently, you’re less likely to be marked as spam by people who forgot they joined your list. Monitoring your email engagement and third-party spam blocklists can also highlight any deliverability issues as soon as they occur. 

Here are 18 email deliverability best practices, organized into groups based on the above factors. Follow these tips to maximize your inbox placement rate and avoid the spam folder.

Without the correct technical setup, your emails are far more likely to go to spam. The good news is that your email service provider should help with most of these steps.  

1. Authenticate your emails with SPF, DKIM, and DMARC

Email authentication builds trust with inbox providers like Gmail and Outlook by protecting you from email spoofing and verifying that the email is coming from who it says it is. Without it, your emails are far more likely to land in spam.

To authenticate your domain, you need to add the following 2 records to your domain’s DNS settings. 

• SPF (Sender Policy Framework): This confirms you’re allowed to send emails from your domain

• DKIM (DomainKeys Identified Mail): This adds a digital signature to prove the email wasn’t tampered with

Most email marketing platforms guide you through the process of adding these authentication protocols to your sending domain. MailerLite goes further by automating the process with many top domain providers. See how it works in the video below.

You can also set up DMARC (Domain-based Message Authentication, Reporting & Conformance), which tells email providers what to do when messages fail SPF or DKIM. It also gives you reports about your sending activity. 

DMARC is essential if you send more than 5,000 emails at a time to either Gmail or Yahoo inboxes. Even if you don’t send at this volume, adding this record to your email domain can help build a deeper picture of trust. 

2. Partner with a reliable email service provider  

The email service provider (ESP) you use has a huge impact on your deliverability. When you send marketing emails via an ESP, you use an IP address that is shared among the various businesses that use the service. 

This is typically a good thing—maintaining your own IP address can be complex and is not something that most small businesses want to worry about. But it also means your ability to reach the inbox is impacted by the other accounts using the same IP as you. 

If your ESP only allows high-quality senders onto its platform, you’ll benefit from the reputation they’ve built up and your messages will land in the inbox. If the service is lax about the types of businesses they allow to send emails, you’re more likely to land in spam.

3. Use a dedicated IP address if sending high volumes

Using a shared IP address on a respected email marketing platform is the best option for most small businesses and creators. But you may benefit from a dedicated IP address if you send a high volume of emails. At MailerLite, we recommend one if you send over 50,000 per week.

A dedicated IP gives you complete control over your email delivery, you won’t be impacted (positively or negatively) by others who use your service. MailerLite makes it easy for you to request a dedicated IP and will even help you set it up.

4. Warm up your IP properly

Dedicated IP addresses need to go through a period of reputation building, known as warming up, before you start using them to send to your entire list. 

Inbox providers like to see a history of good behavior before they trust a particular IP. If you send a high volume of emails from a new IP, they’ll assume you’re a spam sender and direct your messages straight to the trash. 

Start by sending small volumes of emails to your most engaged subscribers and then gradually increase the number of emails you send over several days or weeks. This helps build a positive IP reputation with ISPs.

If you use a dedicated IP through MailerLite, we’ll help with the warming-up process to ensure you benefit from high deliverability right away.  

Since inbox providers look at subscriber engagement when deciding where to send your emails, you must have a list of highly engaged subscribers who interact with your content. Here are tips that can help.

5. Regularly clean your email list

Ensuring you have high-quality subscribers starts with cleaning your current list. This means removing invalid email addresses that are unlikely to lead to engagement. 

List-cleaning tools will typically identify the following kinds of low-quality emails:

• Email addresses that don’t exist

• Email addresses that are likely to bounce

• Role-based email addresses such as sales@yourdomain.com or info@yourdomain.com

• Disposable email addresses

• Email addresses that belong to catch-all domains may not be checked or even exist

Once the low-quality addresses have been identified, you can remove them from your list. 

6. Re-engage or remove inactive subscribers 

Another problematic type of subscriber is legitimate email addresses that no longer engage with your campaigns. 

Since these people don’t interact with your messages, mailbox providers will assume that you're sending to people who don’t want to hear from you, which can reduce your sender score. 

Solve this issue by sending a re-engagement campaign. This is an email you send to people who haven’t interacted with your content in a predefined period. The template below is a good example of a campaign that you can start with right away. 

Exactly how long you wait before a subscriber becomes inactive depends on how often you send messages and what you’re comfortable with. It could be a month if you send messages daily, or 6 months if you only send every few weeks. 

The aim of the campaign is to catch the subscriber’s eye with unique content such as a special offer. You can also simply ask the inactive subscriber to open the email to stay on your list. 

Once you’ve sent the email, give people a week to interact with it. Then remove anyone who doesn’t open the message from your list.

7. Implement double opt-in for new subscribers

Once your list is clean, ensure that all new subscribers are high-quality. Double opt-in is an easy way to do this since subscribers who enter their email address in your form also have to click a link in a confirmation email before joining your list. 

This makes it much harder for people to join your list with fake email addresses or enter the wrong email address by mistake. MailerLite users can easily turn on double opt-in in their form settings.

The result is that your list will be full of email addresses that belong to real people, increasing the percentage of recipients who read and engage with your messages.

8. Only email people who want to hear from you

Always ensure your subscribers are people who want to hear from you. Use opt-in consent on your forms so subscribers know exactly what they are signing up for. This can be through a signup form, a newsletter opt-in, or a checkbox during checkout. 

Remember that even legitimate forms of opt-in can result in low-quality subscribers. For example, if you offer people a freebie or discount to join your list, they might ignore your content after receiving the offer.  

With that in mind, group or segment your subscribers by their sign-up method and keep track of how each group engages with your list. Be proactive in removing subscribers who sign up via methods that lead to low engagement.

Finally, never buy email lists. At best, you’ll get a list of people who haven’t opted in to hear from you, leading to low engagement. At worst, the list could be full of fake addresses, bots and spam traps that could destroy your email sender reputation. 

Plus, in many regions, you’re breaking the law when you send to people who didn’t opt in to hear from you.

9. Include an unsubscribe link

It sounds counterintuitive, but adding an unsubscribe link to your emails can help with deliverability. People who are free to unsubscribe from your content are less likely to mark you as spam. This is, unsurprisingly, a good thing for your sender reputation. 

When people unsubscribe, they are also less likely to ignore your emails, ensuring you keep a high percentage of people engaged. 

Plus, privacy regulations like CAN-SPAM and GDPR require you to include an unsubscribe link in your messages—you may get a fine if you don’t add one!

Your content impacts your delivery rate in 2 ways:

1. Inbox providers look at email engagement to decide if a message is spam, and good content can lead to high open rates and click-through rates. 

2. Inbox providers assess the content to see if it shows signs of spam.

Here are some factors to consider that can help you create deliverability-boosting content.

10. Write subject lines that people open

Your subject line has a big impact on whether people open your emails. This can affect deliverability since inbox providers are more likely to send your messages to the main inbox if they can see that people are opening them. 

With that in mind, spend time writing high-quality subject lines that stand out in the recipient’s inbox. 

There are many strategies you can try. Experiment with different topics, add emojis, use personalization, ask questions, or use keywords that commonly lead to opens. This article on subject line best practices has plenty of tips to try. 

The key is to keep track of what type of subject lines generate higher opens and then reuse these strategies. 

You can also use A/B testing to test the performance of 2 subject lines for the same email. By sending the winning version to the majority of your list, you’ll get more opens. Plus, consistent A/B testing gives you a clear idea of what works with your audience. 

11. Ask subscribers to whitelist you

When people join your list, ask them to whitelist your business. There are several ways to do this. They can:

• Add your address to their contacts

• Mark your messages as important

• Move your email from the promotions tab to the main inbox

These are all signs that show inbox providers that your subscribers value your content, which can lead to higher deliverability. 

Also, consider asking people to reply to your emails. Replies are another valuable form of engagement that ESPs look at. 

12. Avoid creating content that gets mistaken for spam

Content can trigger spam filters if it appears similar to known spam messages. Avoid using spammy language, which is typically classed as language that is either too good to be true, pushy, or desperate.

Check the table below for examples of each type of content. 

Your messages aren't guaranteed to land in the junk folder if you use these phrases. But including them can contribute to your messages looking spammy.

13. Balance text-to-image ratio

When inbox filters started analyzing email content to decide which messages to send to the junk folder, spammers used all-image emails to bypass these checks. This resulted in inbox providers being more likely to send all-image emails to spam. 

As email filers have become more sophisticated, emails with a high ratio of images aren’t quite as problematic as they once were. But they can still contribute to your message being sent to the spam folder when combined with other signals. With this in mind, we recommend not sending emails with a high ratio of images to text. 

With visual drag and drop builders like the one offered by MailerLite, it’s easy to build beautiful emails anyway. Check out the templates below to see examples of the kind of content you can create. 

Plus, these messages provide a better user experience since they are more responsive to different display sizes, more accessible to a wide variety of recipients, and can include more interactive email elements than image-only messages. 

14. Provide relevant content

Our e-commerce email marketing statistics report shows that emails targeted at certain subscriber groups or automated based on actions get far higher engagement than general campaigns.

With this in mind, consider sending emails targeted at different groups or segments and setting up automations that go out to subscribers at the exact time people want to receive them. When you do this, your engagement will increase, which can make you less likely to land in spam. 

15. Let recipients choose what to receive with a preference center

A preference center lets people control the content types they receive from you. It lets people who don’t want to receive a particular type of content opt out without leaving your list entirely. 

Here’s an example of how this could work. Imagine you have a daily email newsletter and a weekend roundup; you could use the preference center to let people opt out of the daily messages. 

The result is that they’re more likely to engage with your content. Plus, you’ll keep subscribers who might otherwise have unsubscribed. See the preference center we use at MailerLite in the screenshot below.

Following good sending practices can help increase engagement. Plus, monitoring your campaigns and blocklists can help you identify problems fast and take action to solve them. 

16. Maintain a consistent email sending frequency and schedule

Sending emails at a consistent sending cadence can improve deliverability by ensuring that people know what to expect from you. 

For example, if you stop sending messages and then start again a few months later, people may have forgotten about you and mark your emails as spam. 

Likewise, if you currently send a weekly email and then suddenly start sending twice every day, people may find the volume too much. They’ll ignore your messages or mark you as spam. 

17. Monitor email metrics 

Monitoring email engagement metrics won’t impact your deliverability, but it can highlight problems so you can fix them. 

• Open rate shows how engaged your audience is. A drop in open rates could also highlight email deliverability issues

• Bounce rates show the percentage of emails that couldn’t be delivered. These could be hard bounces, which happen when you send to addresses that don’t exist, or soft bounces, which happen due to temporary errors. If you consistently have a high percentage of bounced emails, look at how you collect addresses, as you may be attracting bots. 

• Spam complaints are when someone marks your message as spam. A high spam complaint rate suggests that people either didn’t sign up for your messages or don’t find the content valuable. Both Google and Yahoo require your spam rate to be under 0.3%.

If you notice issues with any of these metrics, take steps to solve them sooner rather than later.  

18. Set up blocklist monitoring

Email blocklists are lists of IP addresses or domains that are suspected of sending spam emails. If your domain or server IP ends up on one of these lists, your emails might be blocked, sent to spam folders, or rejected entirely by receiving mail servers.

Inbox providers use these lists to identify spam, so ending up on one is often the cause of a sudden drop in deliverability. 

Blocklist monitoring tools like MailerCheck help by tracking all the main blocklists and notifying you if your IP or domain is added to one. You can then take steps to remove your business from the blocklist. 

Follow the above tips to start improving your email deliverability. Start by ensuring your sending infrastructure is set up correctly and consider moving ESP if the problem persists. 

Then you can look at your content and subscribers to ensure that you’re only sending high-quality content to real subscribers who want to hear from you. 

Ultimately, email deliverability will have a huge impact on the success of your email marketing campaigns, so start prioritizing it today!