A successful cold email outreach goes beyond sending high-quality emails to your audience. It's also about ensuring those messages actually reach them.

With email service providers tightening their spam filters, getting peak cold email deliverability is becoming increasingly difficult. That's why learning how to do a cold email deliverability audit is so important.

Deliverability factors—like your email list, sender reputation, and authentication protocols—determine whether your messages end up in inboxes or spam folders.

This article is your one-stop shop, walking you through each step of the process to assess your deliverability and supercharge your cold email outreach.

Understanding Email Deliverability and Its Importance

Email deliverability measures how successful an email is at reaching the intended recipient's inbox without being flagged as spam or bouncing back. Simply put, it's about ensuring your audience gets and reads your message.

Without good deliverability, your cold emails might never see the light of day, no matter how compelling your content or offers are. Poor deliverability translates to missed opportunities, lost revenue, and a tarnished sender reputation.

But what exactly influences email deliverability? Keep reading.

Identifying Key Deliverability Factors

Several factors determine email deliverability to varying degrees. Some of the most important ones include:

  • Sender Reputation: This is your email marketing track record. Have you been sending legitimate content, avoiding spam triggers, and keeping your bounce rates low? A good reputation increases the chance of inbox placement.

  • Recipient Engagement: Do the recipients on your list really open and then click the email you send them? High levels of recipient engagement tell ISPs that you are a good sender of targeted content, and this will translate to better deliverability.

  • Email Content and Design Quality: Are the emails in the proper format, free of spammy elements, and relevant to your audience? Your email quality can either make or break deliverability.

  • List Hygiene: One more key factor that determines whether or not your cold emails will reach inboxes is the presence of inactive recipients and invalid email addresses on your list.

In an age where people are flooded with emails daily, getting noticed is half the battle. And that's what deliverability aims to solve. So, what steps should you take to perform a comprehensive cold email deliverability audit? Let's find out.

Step 1: Perform a Pre-Audit Checklist

Before starting your audit, get everything you need ready and organized to keep the process silky-smooth. Here's our checklist of how to prepare:

  1. Define Your Goals: What do you hope to achieve with your audit? Whether it's reducing spam complaints or boosting engagement, clear goals keep your efforts focused.

  2. Identify Stakeholders: Decide who will be involved in the audit process. Is it just you? Or are there key personnel you need to bring on board?

  3. Gather Data: Research and compile all relevant data about your cold email campaigns—opens, relies, clicks, bounces, and others. Having everything organized saves time and helps analysis.

  4. Choose Your Tools: We'll recommend some useful ones in a moment but choose tools that match your goals and technical comfort level.

  5. Set a Realistic Timeline: Don't expect overnight fixes. Dedicate enough time to conduct a comprehensive deliverability audit and work on the results.

Tools for Email Deliverability Audit

Now that you have a clear plan of action, here are a few tools that could come in handy during your cold email deliverability audit:

Key FunctionsOur Pick
AnalyticsQuickMail helps you uncover key metrics like opens, replies, clicks, and bounces with send-day attribution for better deliverability monitoring
IP and Authentication CheckerQuickMail monitors DNS, IP blacklist status, and authentication protocols like SPF, DKIM, DMARC
Spam TestSpamTester.ai checks your email for common spam triggers
Email VerificationNeverBounce verifies and cleans up your email list by removing invalid or inactive email addresses
Sender Reputation CheckerSender Score checks your domain reputation score to show your current standing and areas of improvement
DeliverabilityMailflow warms up your inbox to optimize your cold email deliverability

For a complete list of our recommended email deliverability tools, check out this guide.

Step 2: Analyze Your Email List Health

Your email list is the lifeblood of your email marketing efforts. As such, maintaining its health and quality is key to achieving optimal deliverability. Here's how to ensure your list is in tip-top shape:

Observe Best Practices for List Hygiene

A clean email list is better than a bloated one. To get the best out of your email list, make regular list hygiene a top priority.

How? Set aside time to get rid of invalid email addresses and segment inactive prospects. Not only does this improve your deliverability, but it also ensures you're targeting only the most interested readers.

Another important best practice is making it easy for users to unsubscribe if they're no longer interested. This paints you in a good light and is legally required under many privacy and anti-spam laws worldwide.

For advanced users, Quickmail provides AI-assisted unsubscribes by automatically detecting an unsubscribe reply and handling it for you.

Segment Your Email List

Segmentation is a key driver of successful email marketing. It involves dividing your email list into smaller, targeted segments based on demographics, interests, actions (e.g., incomplete product demo sign-ups), and so on.

Targeting recipients by segments lets you deliver more relevant content. This translates to better engagement and, ultimately, higher deliverability.

Leverage Re-engagement Campaigns

Before writing off leads that have gone cold, consider re-engagement tactics to reignite their interest and keep them on board.

We're talking:

  • Compelling content that sparks curiosity and reminds them of your value

  • Incentives like discounts, exclusive content, and early access to new products

  • Detailed information about the benefits of engaging with your product or service

Having optimized your email list health, it’s time to find out what your email marketing track record looks like.

Step 3: Assess Your Sender Reputation

Think of your sender reputation as your email marketing credit score. A high score (good reputation) assures ESPs you're a trustworthy sender, boosting your deliverability. And you can already guess what a bad score does.

Now, let's see how to check and improve your sender reputation.

Evaluate Your IP Address Reputation

The IP address you send emails from plays a big role in deliverability—perhaps the biggest. Why? Many ESPs use IP-based reputation systems to assess how trustworthy you are.

To evaluate your IP address reputation, use tools like QuickMail and SpamTester.ai to uncover red flags like high spam complaint rates or blacklistings. Remember, a bad reputation can place your emails in spam, even with good content.

On a side note, if using a new IP, sending out large email volumes from the onset can trigger spam filters. Instead, start with small batches and increase them over time to build trust with ESPs.

If you can’t avoid sending large email volumes from the start, consider spreading your emails across multiple accounts. QuickMail offers a helpful inbox rotation feature to help with this.

Use Quickmail's Advanced Analytics

To assess and improve your sender reputation, you need to understand your email performance at the most basic level. In other words, you need software that provides deep insights and offers top-tier features to get effective results.

QuickMail's advanced analytics is the answer. How does it work? Like an "X-ray" showing you exactly what strikes a chord with your audience on an email-by-email basis.

It specifically lets you:

  • Experiment with different email templates to see which ones leave a lasting impression on your audience.

  • Use send-day attribution to monitor opens and engagement week over week to catch deliverability issues early on.

  • Try out different subject lines to capture attention and boost open rates

  • See who opened, clicked, or unsubscribed to identify trends and tailor your approach for different segments of your audience.

  • Go beyond raw data and understand how recipients feel about your emails with sentiment analysis.

Next up, let's address the content and design of your cold email itself.

Step 4: Review Your Email Content and Design

Now, let's address your email itself. Non-spammy content in an easy-to-read format gives your audience a value-packed experience, leading to higher engagement and deliverability. 

Much like a magnet, your email content should attract your audience—without triggering spam filters. This means providing relevant, high-quality content that speaks directly to their pain points.

To get it right, keep these dos and don’ts in mind:

Use concise, personalized, and non-spammy subject linesUse ALL CAPS and excessive punctuation (???)
Be straightforward, no matter how tempting it is to “build up”Be fluffy, generic, robotic, or overly “salesy”
Provide value in every cold email, whether it's meant to inform, entertain, or offer exclusive dealsInclude overused spammy words like "FREE!" or "URGENT!"
Opt for a professional font and visually appealing designSend attachments or image-only emails to prospects
Break up text to make reading easy and keep your audience scrollingUse too many images, emojis, or bright, flashing colors
Use clear calls to action (CTAs) to tell readers what steps to take afterLeave out the unsubscribe button, physical address, and email signature

Step 5: Optimize The Technical Aspects of Deliverability

A solid email authentication and infrastructure strengthens your legitimacy, which in turn, boosts email deliverability. Here’s how to optimize it for the best results:

Set Up Email Authentication Protocols

Authentication protocols like SPF, DKIM, and DMARC are essentially calling cards that vouch for your email’s legitimacy. They help prevent phishing attacks and email fraud by confirming that your cold emails really come from you.

Setting them up can be a bit technical, so we recommend consulting an expert for specific instructions and assistance. That said, here's a short summary of what each protocol does:

  • Sender Policy Framework (SPF) clarifies which domains are authorized to send emails on your behalf.

  • DomainKeys Identified Mail (DKIM) adds a digital signature to your emails to let recipients know they truly came from you.

  • Domain-based Message Authentication, Reporting & Conformance (DMARC) verifies your SPF and DKIM records and tells email service providers how to handle emails that fail authentication.

To set up SPF, DKIM, and DMARC protocols, visit your Domain Name System (DNS) settings and include the necessary TXT records following your email provider’s instructions. 

Note: The configuration process may differ depending on the email provider's guidelines.

Regularly Update Your Authentication

Beyond setting up authentication protocols, you need to conduct regular updates to reflect changes in your email infrastructure. For instance, if you change email service providers or domains, your records must reflect this.

Keeping your records up-to-date protects you from ever-emerging security threats and improves your sender reputation. The outcome? Higher deliverability.

Step 6: Monitor and Evaluate Your Campaign Metrics

Now for the final step in our list: Monitoring and Evaluation. This step involves looking for patterns in your data to find out what works and what doesn’t.

Advanced Metrics

Are some subject lines driving higher open rates? Are specific types of content leading to more clicks? The answers help you refine your strategy for better results. Let’s take a closer look:

Interpreting Email Analytics

Email analytics provide a treasure trove of data to help you understand how your email campaigns are performing. After all, knowing what to look for (and fix) is a critical first step in improving your cold email campaigns.

In short, here are five commonly tracked cold email metrics for a crystal-clear picture of your email's performance:

  • Open rate tracks the percentage of recipients who open your email. They vary widely across industries and geographies. A low open rate could indicate subject line issues, relevance problems, or inactive recipients.

  • Reply rate measures how many of your cold emails get a response. For instance, if you send 500 cold emails and get 125 replies, that’s a 25% reply rate.

  • Click rate shows the percentage of people who open your email and click on a link within it. A low CTR might suggest your email content is irrelevant to your audience or not compelling.

  • Positive replies or your conversion rate measures how successful your emails are at generating leads and driving sales.

  • Unsubscribe rate tracks how many of your recipients opted out of receiving your emails.

  • Bounce rate shows the percentage of emails not successfully delivered to recipients' inboxes. A high bounce rate negatively affects your sender reputation and deliverability.

Improving Your Email Open Rates

Perhaps the most critical metric to monitor is your email open rate. To increase your open rates (and enhance deliverability), you need to refine your first impressions.


  • Craft clear, short, and personalized opening lines

  • Use personalization (e.g., recipients’ names) where it makes sense

  • Use compelling hooks to pique interest without resorting to spammy tactics

  • Tailor preheaders to elaborate on your subject lines and entice further

There’s no one-size-fits-all here. Cautiously try out different tactics like emojis, urgency, and curiosity to see what resonates best with your audience.

Check out our best practices for A/B testing to conduct effective experiments for your cold email metrics.

Bounce Rate Analysis

Analyzing your bounce rate helps you learn your email list health and the quality of your email infrastructure. Bounces can be categorized into two main types:

Understanding Hard vs. Soft Bounces

  • Hard Bounces indicate permanent delivery failures (e.g., invalid email addresses and closed accounts). Remove them from your list to improve bounce rates and sender reputation.

  • Soft Bounces are temporary delivery issues (e.g., full mailbox and server issues). They might resolve themselves, but keep track and consider resending the email after some time.

As you dive into your email deliverability audit, let data guide your every action. By taking the steps set out here, you gain insights to improve deliverability and drive a successful campaign.

Ready to Start Your Cold Email Deliverability Audit?

A cold email deliverability audit is an ongoing process. Taking action, tracking progress, and refining your approach are best practices for inbox placement.

However, engaging a reliable partner to guide you through the process remains the best path to success.

Quickmail has everything you need to scale your cold email marketing efforts—from deliverability features to campaign optimization tools.

You can try it out yourself risk-free. Sign up for your free QuickMail trial today