The Ultimate Guide to Email Deliverability in 2025

Just one thing can make or break your next cold email campaign: EMAIL DELIVERABILITY.

With high email deliverability, your emails will always land in inboxes and help you generate high-quality leads.

On the other hand, low email deliverability can ruin your email outreach campaign before it even begins. 

With tighter spam filters and constantly changing algorithms, simply writing a great email isn’t enough—you need to make sure it actually reaches your prospect’s inbox.

If you’re wondering how to maintain optimal deliverability rates in 2025, you’ve come to the right place.

In this ultimate guide, we’ll cover →

• What email deliverability is
• The key factors that affect it
• How you can build email deliverability

And so much more!

Read on and say goodbye to the spam box.

What is Email Deliverability?

Email deliverability measures the number of emails that land in your recipient’s primary inbox.

So, let’s say you’ve sent 100 emails to different recipients and 90 of them land successfully in their inboxes. In this case, you have an email deliverability rate of 90%!

The higher your email deliverability, the better the chances your emails will land in your prospect’s inbox—and grab their attention with what you have to offer.

Is Email Deliverability Different from Email Delivery?

One of the most common questions newbies in cold emailing ask me is the difference between email delivery and email deliverability.

Let me explain what the difference is → 

Email delivery refers to the email just landing in one of your recipient’s folders—whether that’s spam, promotions, social, or inbox. If it shows up in any of those, it’s technically been delivered. Simple, right? 

But when we talk about email deliverability, we’re talking about getting those emails to land in the primary inbox. (It’s a more specific goal.) 

If your email ends up in spam, promotions, or any other folder, it doesn’t really count in terms of deliverability. 

Why is High Email Deliverability Important?

Email deliverability plays a very important role in the success of your cold email campaigns.

Let’s take a how email deliverability supports your overall cold email success.

1. Increased Sender Reputation
2. Improved Engagement Rates
3. Lets You Send More Emails Every Day
4. Helps You Succeed in Cold Email Campaigns

1. Increased Sender Reputation

First and foremost, good email deliverability helps you to build a higher sender reputation.

How? 

Well, if most of the emails you’re sending land in the recipient’s primary inbox, it means that they have successfully cleared the ESP’s spam filters. 

And if your emails are consistently landing in primary inboxes, it helps to build the reputation!

2. Improved Engagement Rates

Emails that reach the primary inbox are set for higher engagement, such as clicks, responses, and conversions. 

On the other hand, if your emails get stuck in the spam or promotions folder, they will never get seen, and engagement will suffer.

3. Lets You Send More Emails Every Day

One problem that many cold emailers have is the ESP’s daily email sending limit. 

Email deliverability helps you to maintain a strong sender reputation.

When your emails consistently land in the inbox and don’t get marked as spam, ESPs see you as a trusted sender.

This reduces the chances of your account without tripping spam filters, allowing you to send more emails while staying within the limits set by the ESP

4. Helps You Succeed in Cold Email Campaigns

Good deliverability is what makes cold outreach work — without it, even the best emails won’t get results. 

When your deliverability is strong, more people actually see your emails, which means a higher chance of getting replies and booking meetings. 

Moreover, it also helps in building a good reputation with ESPs, ensuring that your future emails keep reaching inboxes.

How Can You Measure Email Deliverability?

If you want to improve your email deliverability, the first thing you need to do is measure it accurately. 

Don’t worry: it’s neither challenging nor do you have to do it manually because there are several dedicated tools you can use to measure your email deliverability.

Let’s take a look at three such standout platforms:

1. Google Postmaster Tools
2. SenderScore
3. MX ToolBox

1. Google Postmaster Tools

Postmaster Tools is Google’s native, free-to-use platform through which you can analyze and visualize your email-sending patterns and metrics.

It allows you to easily measure the following:

• Email spam and spam complaint rate
• Bounce rate
• IP and sender reputation
• Delivery rate

Simply put, Google’s Postmaster Tools helps you understand not just your email deliverability rate but also all the metrics associated with it. 

2. SenderScore

One of my go-to tools for measuring email deliverability is SenderScore.

It offers a full suite of email deliverability tools that you can use to easily measure your email account’s sender reputation, bounce rates, and spam rates.

Plus, if you think you’re suffering from poor email deliverability, SenderScore will give you a list of benchmarks you can monitor to improve your sender reputation and deliverability in one go!

3. MX ToolBox

MX ToolBox is an easy-to-use tool for tackling one of the most critical elements of email deliverability: authentication.

Its primary function is to establish and verify your SPF, DKIM, and DMARC records. It also enables you to protect your email infrastructure from phishing and spoofing attacks.

One of the most important reasons why I recommend MX ToolBox is that it provides several other key features, such as threat intelligence, inbox placement rate, and blocklist monitoring.

The Factors that Can Affect Email Deliverability

Various factors determine email deliverability: some are related to your email infrastructure, while others are related to the content of your emails.

In this section, we’ll take a look at the 7 factors that have the greatest impact on your email deliverability rate:

1. Spam Complaints
2. Shared IP Addresses
3. Bounce Rates
4. Poor Sender Reputation
5. Spammy Language and Phrases
6. Too Many Images, Links, and Attachments
7. Suspicious Email-Sending Patterns

1. Spam Complaints

Spam complaints are the #1 factor that can make or break your email deliverability.

For example, if you’re sending emails that your prospects think are irrelevant, they’re very likely to mark it as spam or, in the worst case scenario, even block your email account!

This will drastically lower your email deliverability, as your ESP will assume your account is an untrustworthy sender.

2. Shared IP Addresses

An IP Address is your window to the Internet: it’s a series of numbers through which your Internet Service Provider determines your identity.

If you’re using a shared IP address, it means that thousands of other internet users might also be using it to connect to the internet.

And if anyone of them are engaging in suspicious or malicious activity, your ESP might lower the IP reputation of the entire network of users!

So, even if you are not using the internet or your email account for malicious purposes, it will negatively affect your email deliverability rate!

3. Bounce Rates

If you’ve ever made a small error while typing your recipient’s email address or used an unverified email, you might have received a delivery report error: your message could not be delivered.

This is what we call a bounced email. And the number of emails that result in such errors makes up your email bounce rate.

There are two types of email bounces: hard bounces and soft bounces.

Hard bounces occur when your recipient’s email address is either invalid or incorrect. This means the email cannot be delivered at all. From what I’ve seen, hard bounces can also result from poorly compiled email lists or email lists from unverified B2B data providers.

On the other hand, a soft bounce can occur because of several reasons: your recipient’s ESP server is down or their mailbox is full.

However, both hard and soft bounces will lead to poor email deliverability.

4. Poor Sender Reputation

Think of Sender reputation like the credit score of your email account: with a poor sender reputation, more and more of your emails will land in the spam box.

Sender reputation, much like email deliverability, is itself determined by your bounce rate, spam rate, and email authentication.

5. Spammy Language and Phrases

What do almost all malicious email senders have in common? 

They all use spammy words like “Once in a lifetime opportunity,” “You’re a winner!” and “Get rich quick…”

To deal with such malicious email senders, ESPs have developed spam filters that look for these phrases in all email communications.

In other words, if you’re using such phrases in your sales and marketing emails, ESPs might flag your email account as suspicious. 

And this will have a negative impact on your email deliverability!

6. Too Many Images, Links, and Attachments

Many fraudulent emails include links that take you to third-party websites that might harm your financial well-being. 

For this reason, you might have noticed that many of the emails in your spam box contain too many attachments, images, or links.

Similarly, if you’re sending emails to your prospects that have many proposals, powerpoint presentations, or links to your website, the ESP might route your emails straight to the spam folder!

7. Suspicious Email-Sending Patterns

The last thing that I’ve often noticed, which results in poor email deliverability, is an irregular email sending pattern.

For instance, if you send 1,000 emails today in the morning and by afternoon you are sending 1,000 more, you might alert your ESP!

It might think that you’re engaging in suspicious behavior and, therefore, either send your emails to spam or, worse, put your email account on a spam blacklist!

How to Build Email Deliverability: Best Practices

Till now, we’ve examined in detail what not to do. 

Now it’s time to know how you can improve and maintain a high email deliverability rate.

1. Switch to a Dedicated IP Address
2. Authenticate Your Email Account
3. Stick to ESP Daily Sending Limits
4. Use Double-Opt-In Subscriptions
5. Warm-Up Email Accounts
6. Never Use Spammy Language
7. Avoid Including Too Many Links or Attachments
8. Clean Your Email List
9. Send Personalized Emails
10. Monitor Key Deliverability Metrics

1. Switch to a Dedicated IP Address

First and foremost, you should switch to a dedicated IP address. It will give you complete control over your internet activities and ensure that you don’t face the negative consequences of someone else’s actions.

There are three ways you can get a dedicated IP address: 

• Through your current ISP
• Via a hosting network like Hostinger
• By requesting one from a VPN service like NordVPN

While getting a dedicated IP address might seem like an extra task, I highly recommend that you get one if you want to ensure good email deliverability!

2. Authenticate Your Email Account

Setting up these email protocols is very important to prove your identity to receiving mail servers →

• SPF: Sender Policy Framework 
• DKIM: Domain-Keys Identified Mail
• DMARC: Domain-based Message Authentication, Reporting and Conformance

3. Stick to ESP Daily Sending Limits

As I have already mentioned, every ESP has a strict daily email-sending limit.

And if you bypass this limit, your email will likely not even be delivered, let alone land in the primary inbox.

To ensure that you retain a high email deliverability rate, I recommend strictly adhering to the ESP’s sending limits.

One solution to this problem is to create multiple secondary domains and distribute the email volume among them.

4. Use Double-Opt-In Subscriptions

Double opt-in is a simple yet powerful way to protect your email deliverability and stay legally compliant. 

So what is it? 

Well, it is a 2-step confirmation process where the prospects confirm in two stages: once by signing up, and again by confirming via email that you are emailing people who genuinely want to hear from you! 

This may sound like an extra step, but it can make a huge difference! 

5. Warm Up Email Accounts

One of the easiest ways to guarantee high email deliverability is to warm up your email account.

It is a strategic process where you gradually increase sending volume to engage in real conversations with email accounts that have a solid sender reputation.

6. Never Use Spammy Language

As we’ve seen, spammy language can drastically lower your chances of landing in recipients’ inboxes. To avoid this, I recommend that you always double-check your copy for any potentially spammy phrasing. 

This is especially important if you’re planning to send cold emails: if even a single email in your sequence contains spammy words, it might mess up your entire campaign!

7. Avoid Including Too Many Links or Attachments

If you’re emailing a recipient for the first time, you should never include any links or attachments.

Trust me: I’ve seen several cases where even the most important of emails are routed to the spam folder just because they contained many links, attachments, or images.

8. Clean Your Email List

If you want to avoid hard bounces, you should always clean your email list before using it for cold email or outreach campaigns.

This is important if you’re buying email lists from data vendors. Often, such lists contain invalid or outdated email addresses, which might lead to hard bounces and, therefore, low deliverability.

I suggest that you use an email verification tool like NeverBounce to clean your email list. 

9. Send Personalized Emails

One of the best ways to ensure that you’re always landing in inboxes is to send personalized emails. This is due to several reasons: 

• Recipients are less likely to mark personalized emails as spam
• You will avoid triggering spam filters by positioning your email as a unique message rather than a generic one
• Personalized emails are likely to have a higher reply rate, which will lead to a higher sender reputation and high email deliverability

10. Monitor Key Deliverability Metrics

One thing I’ve learned the hard way is that you can’t improve your email deliverability without constantly measuring it through numbers. This is because ESP behavior is often unpredictable: a small change in its policy can lead your email deliverability to take a hit!

Monitor key metrics continuously to ensure that your email deliverability is always on track. 

These include:

• Spam Rate
• Bounce Rate
• Authentication Success Rate
• Inbox Placement Rate
• Open Rate

Supercharge Your Email Deliverability and Never Miss the Inbox!

Email deliverability is the only thing that stands between you and a successful email outreach campaign.

Now, attaining maximum email deliverability may seem challenging with all the different things you need to watch out for. 

However, if you follow all the steps I’ve outlined above, I’m confident that you can achieve and maintain high email deliverability.

And if you’re looking for a one-stop solution to build your email deliverability without wasting time or energy, I recommend using TrulyInbox.

Explore its features for yourself and witness how easy it is to achieve high email deliverability!

FAQs: Guide to Email Deliverability

1. How Do I Improve My Email Deliverability?

Here are the best ways to improve your email deliverability:

• Use an automated email warm-up tool
• Switch to a dedicated IP address
• Authenticate your email accounts
• Always send personalized emails
• Avoid sending emails with links, images, and attachments

2. What Is a Good Deliverability Rate for Emails?

As per the cold emailing experts, a good email deliverability rate is somewhere between 90 and 98%.

3. What Determines Email Deliverability?

There are five main factors that determine email deliverability:

• Email sending frequency and pattern
• Email authentication and infrastructure
• Email content (including links and attachments)
• The quality of your email list
• Spam complaints and requests

4. What Hurts Email Deliverability?

There are four major things that can hurt email deliverability:

• Violating the ESP’s sending limits
• Not authenticating your email account
• Sending emails with spammy words, images, attachments, and links
• Not personalizing your emails