The Ultimate Guide to Cold Email Deliverability for 2024

Email deliverability is an important topic for anyone using email in their business.

If you're sending cold emails to people that match your buyer persona with a perfect pitch, surely you'll get a high reply rate and book lots of meetings — right?

Not necessarily.

So, how do you ensure you land in the main inbox?

This guide will show you actionable ways to ensure your emails land in your prospect’s main inbox, where they’re going to read them and reply. 

We’ll discuss:

Let's jump straight in.

What Is Email Deliverability?

First, let's start by defining what we mean by email deliverability.

Email deliverability is how well your email can deliver messages to a recipient's inbox. Good marketing email deliverability will mean your email lands in their main inbox folder. If you've been using email messages naturally for a few months with co-workers and clients, chances are that your email deliverability will be good.

But, if you plan to launch a cold email campaign, your email service provider will notice that your activity is changing.

If you send ten emails by hand to your email marketers on Monday but send 200 out all at once on Tuesday, it won't look right.

Email providers like Outlook and Gmail will see that you're using your email in an unnatural way, and you'll end up landing in the Promotions category, or worse, Spam.

If that's the case, no one will reply to you. Your cold email campaigns won't generate any new sales, and you'll be back to paying for Facebook Ads.

What's a Good Email Deliverability Rate?

While it's hard to find exact figures on what a ‘good' deliverability rate is, as Google and Microsoft are both secretive about their email data.

As well as that, you need to think about multiple email engagement metrics, including the percentage of emails delivered, those landing in the main inbox vs. spam, and emails bouncing.

To have any chance of success with cold email, you'll want to have an overall deliverability of at least 95%. Anything lower, and you have a delivery rate problem.

You'll also want to ensure those emails land in your prospects' main inbox, not in a spam trap.

A simple way to check your deliverability is using our deliverability report.

It shows you where your emails are landing depending on the ESP you're sending to, as well as showing you if your SPF and DKIM records are working as expected.

When it comes to bounce rate, a well-targeted outreach campaign shouldn't have many bounces, if you've verified the emails before sending.

That said, always aim for 3-5% or less.

If you consistently see a bounce rate above that, it's a sign that you need to spend more time validating your emails.

What Factors Affect Email Deliverability?

There are a variety of factors that affect email deliverability, but let's start at the top. These are the basics – if you get them wrong, you'll see poor deliverability rates and struggle to get into any primary inbox.

1. Configure Your Technical Foundations

If you've just purchased a new domain, you'll need to ensure your technical foundations and email servers are solid.

That means you'll need to configure the following records:

  • SPF

  • DKIM


SPF, or Sender Policy Framework, tells email service providers that it's you sending your emails and prevents people forging emails from you. It's essential if you want your email address to be trusted by ESPs.

DKIM stands for DomainKeys Identified Mail, and it's a more advanced authentication protocol that tells ESPs that your email wasn't modified on the way to the sender. Without it, there's a risk of your emails being tampered with and having the contents changed, and spam filters won't want to send risky emails to anyone's inbox.

DMARC stands for Domain Message Authentication Reporting & Conformance. Having a DMARC policy tells ESPs that your emails are protected by SPF and SKIM.

If you don't have DMARC, there's a possibility that your recipients' inbox will send your email straight to spam as it's untrustworthy.

Having your SPF, DKIM, and DMARC records in place is essential. If you don't set them up, your emails will be sent straight to spam.

Most hosting providers and ESPs will have instructions on setting these up if you've never done it before.

Once you've added them, run a check with Google's Check MX tool. This will show you if you've set your records up correctly, and if not, you'll see a notification of which ones still need to be configured.

If you see the green checkmarks, you're set.

2. Start With a Low Send Volume

If you buy a new domain and instantly start sending hundreds of emails, you'll be flagged as a spam email, and the email address will be useless.

Email send volume is a key reason for poor deliverability, often overlooked by anyone eager to start their cold email campaigns.

Start by sending a low volume of emails out, and slowly work your way up to avoid spam complaints and unsubscribe rates.

For example: 

  • Week 1 + 2: Purchase domain, only use it with co-workers and existing clients

  • Week 3: 5 emails per day

  • Week 4: 10 emails per day

Over time, you'll be able to ramp up your email sending volume.

As well as that, assuming you're sending good and legitimate emails, you'll be getting a good enough reply rate to keep you busy.

If you need to send lots of emails, consider using multiple email accounts instead of just one.

QuickMail has a useful inbox rotation feature to help you spread email volume across your team and company.

Add your whole team's email accounts, decide whose accounts will be used, and you'll be able to safely send more emails than you would be from a single account.

Even when your account has been warmed up, you'll still need to be aware of sending limits.

For example, Gmail users are limited to 2,000 emails per day (you shouldn't get anywhere near that), and Outlook users are limited to 1,000 emails to ‘non-relationship recipients,' which means people you've never interacted with before.

You shouldn't be sending that many cold emails daily, but it's worth keeping in mind.

3. Your Email Content Matters

Another factor affecting deliverability is your email content itself.

Are your recipients engaging with it?

Are they clicking on links? Replying to you? Marketing it as important?

All of these factors affect how ESPs see your email activity, which is why it's so important to send relevant content that is genuinely good and useful.

The quality of your email list matters as well. If you've done your research to build a prospect contact list that will be genuinely interested in your emails, you'll see a high engagement rate.

On the other hand, if your list is poorly chosen, you'll get no engagement, and in turn, it'll hurt your future email deliverability.

We'll look at more ways to improve your email content further down in this article.

How to Warm Up Your Email Address

If you care about email deliverability, you've probably heard of the need to warm up your email address.

When you first buy a domain name and start sending emails, the inbox you're sending from isn't seen as trustworthy by ESPs, which could lead to poor deliverability rates.

However, to speed up the trust-building process, you can "warm it" up and build a domain reputation.

What this traditionally involved was emailing co-workers, clients, and other people you knew would reply to you.

Nowadays, there are email warm-up tools such as MailFlow (it's free to use), which will automatically warm up your email account by sending emails to other people, creating automatic responses, and marking them as “important.”

Within MailFlow, you'll be able to see a handy report showing you where your emails are landing.

Over time, this will show ESPs that you're using your inbox in a regular way, getting engagement, and don't deserve to land in the spam folder.

Cold Email Deliverability Best Practices

If you plan on using cold email for the long term, you'll need to know the best practices to ensure long-term success.

1. Use Cold Email Software, Not Email Marketing Software

Cold email software is different from email marketing software.

Software like Mailchimp isn't designed for personal outreach, and email marketing campaigns that require uploading prospects who haven't explicitly opted in is against their TOS.

If you're sending cold outreach campaigns and get reported, not only will you land in spam, but you'll quickly get banned from using Mailchimp.

The same applies to tools like ConvertKit, ActiveCampaign, and MailerLite.

Instead, choose a platform specifically designed for cold emailing. These usually have different features that prioritize engagement, such as replies over clicks, and you'll usually have a plain text editor instead of an HTML editor to design.

2. Use a Cold Email Domain

No matter how good your cold emails are, there's always going to be a risk of your domain being blacklisted. If that happens, your whole domain is going to be rendered useless. You won't be able to communicate with prospects or existing clients.

So, what does this mean in practical terms?

When buying your domain name, buy a similar domain to send your cold emails from.

For example, if your website is, you shouldn't be sending emails from that.

Instead, use a different domain and email account for your outreach, such as,, or even a variation of your domain name, like

That way, if you're ever labeled as a spammer by ESPs, it won't affect your main domain.

3. Mix Up Your Sending Times

If you send 50 emails every morning at 9 am, it will look suspicious. Change the time of day and number of emails you send to ensure your account looks natural and doesn't get flagged for suspicious activity.

You can easily do this by creating schedules in QuickMail. Start your email sending at different times every day, with a various number of prospects.

4. Check Your Sender Score

Sender Score is a metric by Return Path that looks at indicators of how good your email reputation is.

It looks at indicators like:

  • Whether your emails are being marked as spam

  • How engaged your recipients are

  • If you're on email blacklists

It's not a perfect way to improve your deliverability, but it'll show you where there are improvements, and fixes that you should make.

For example, if your emails aren't getting enough engaged subscribers, you know to change how you're emailing people, update your call to action, or let your email account rest by only emailing colleagues and clients.

5. Avoid Open and Click Tracking

It's tempting to track opens and clicks in your emails to help you understand how good your emails are, but unless it's absolutely necessary, it's often better to avoid it.

If you want to track opens, a small tracking pixel is added to your emails in the form of a small image. If you're tracking links, a redirect is added to your links to enable your email software to track the clicks.

Spam filters prefer not to let emails with images and redirects through if they catch them, so they risk hurting your deliverability.

It's nice to see key email marketing metrics tracking performance, but it's not as important as your emails landing in your prospects' inboxes.

6. Personalize Every Email

Every email you send should look natural. Make sure to personalize every single email in your campaign.

Yes, it's going to take longer than if you send the same email template to every prospect, but it'll show ESPs that you're using your email in a natural, human way instead of focusing purely on volume.

One simple strategy to do this is to personalize the first line of every email you send, as well as using people's name, company name, and other relevant information. When you write your cold emails, simply add your merge tags to the email, and the personalized fields will show up.

As well as being better for deliverability, it's going to ensure your emails get engagement.

After all, no one will reply to an email that you've clearly sent to hundreds of people without changing anything.

7. Optimize Your CTA for Replies

While you may want to get high open rates and high CTRs on your emails, they don't matter unless you're getting real engagement from email recipients in the form of replies.

Rather than spending hours coming up with interesting subject lines, focus on writing a personalized, engaging email with a clear call to action.

Examples of call-to-actions that can work are:

  • Is that something you'd be interested in?

  • Are you available to chat?

  • What's your biggest challenge around {[topic}} right now?

Depending on your email, the call-to-action will vary – but make sure it's a clear question that incites a reply.

Don't ask people to click links, and don't make them think too hard before replying.

The good thing about questions is that people can respond negatively, as well. If they're not interested, chances are they'll be happy to reply with a simple “No, thank you.”

The benefit for your deliverability is that your ESPs will still see that as a better outcome than no reply because it shows you're getting engagement.

8. Clean Your Prospect List

One of the main reasons for poor deliverability in the long term is that you're sending too many emails to non-existing addresses that bounce or to people that don't reply.

To avoid this, there are two steps you need to take.

First, spend longer building your prospect list. Ensure every person you cold email is going to be interested in what you have to say or at least has a very good chance of being interested.

This means your sales prospecting process may take longer, but it'll result in campaigns with higher engagement.

Next, you'll need to ensure you're never emailing out-of-date email addresses.

Use tools to find publicly available email addresses for your prospects, and never contact someone unless you can verify their email address is correct.

9. Test Your Emails Before Sending

Before sending your cold email campaign out, run your emails through a tool like spamtester.

It's designed to “test the spammyness of your emails,” which means it scans your emails for common factors that could mean your emails get flagged as spam by mail servers.

It'll show issues such as:

  • No DKIM configured

  • Whether you have too many images in your message

  • No unsubscribe link in your email

You don't need to follow every guideline that spamtester recommends, as it's an automated tool and can miss the email context.

However, if there are fixes you can make to your technical setup, for example, a missing DKIM signature, then you should always resolve it before you start an outbound campaign.

10. Add an Unsubscribe Link

No matter how good your cold emails are, they're still unsolicited. Not everyone will be happy to receive them from you.

A simple way to lower the chances of someone marketing your emails as spam is to include an unsubscribe link.

You can include it in your email and digital signature, or, include it in the email header, which is more subtle.

Remember, even if you include an unsubscribe link, if your cold email feels like spam to your recipient, chances are, they'll still mark you as spam without unsubscribing.

That‘s why it's so important to focus on the quality of every email you send out to your email clients.

If you're using QuickMail, here's a guide to adding unsubscribe links to your email signature or header.

For more best practices, check out our latest webinar on email deliverability:

Tools to Check and Improve Email Deliverability

Below is a list of free email marketing tools that will help improve your email deliverability. For a more complete list of both paid and free tools, check out this article.

1. MailFlow

If you're sending cold emails, you need a well warmed up email address. Assuming you don't want to do it manually, using an email warming service is a great shortcut.

MailFlow is an email tool that will send emails to people everyday, simulating real exchanges between email accounts.

As MailFlow takes spam seriously, you'll never interact with spamming accounts.

Your emails will receive replies from recipients automatically, and over time, you'll be seen as trustworthy by inbox providers.

MailFlow's email warm-up tool is free to use, and has a native integration with QuickMail for its users.

You'll also have access to our entire sales outreach platform to send, schedule, and follow-up with your prospects automatically.


Spamtester is a useful, simple tool to check your email deliverability health.

To use it, send your cold email template to the unique email address it gives you.

It'll then run a check on the email, looking for spam trigger words, unnecessary links and images, and check for technical issues with your email account.

You should be aiming for at least a 9/10 score. Anything below and it's worth taking the time to solve the issue before starting a campaign.

3. Postmaster Tools

If you're sending a high volume of emails across your team, Postmaster Tools is useful.

It shows you data on your email account such as:

  • Spam Rate

  • IP Reputation

  • Sender Reputation

  • Delivery Errors

If your team sees a deliverability drop for no reason, you can diagnose it with Postmaster Tools.

4. Check MX

Before sending any cold emails out, your technical foundations need to be in place. Check MX is a great free tool for this.

It's simple – add your domain name, and it'll automatically check if you have all the necessary records in place.

If you've forgotten to configure your DKIM signature or SPF records, it'll show you.

Wrapping Up

If you want to see results from your cold email campaigns you need to get your deliverability in check.

If a large percentage of your emails aren't even arriving in your prospects' inboxes, you won't get results.

Follow as many of the steps here as you can before launching your cold email campaigns, and use them to diagnose any problems with deliverability in the future.

While it's cliche, always focus on quality over quantity.

When you’re ready to start sending personalized cold emails, start your 14-day free trial QuickMail to automate the process.