Email Deliverability Audit: The Complete Guide

What is an email deliverability audit? An email deliverability audit is a systematic review of all factors determining whether your emails reach recipients’ primary inboxes or spam folders. It examines sender reputation, authentication protocols (SPF, DKIM, DMARC), bounce rates, engagement metrics, and content quality to identify and fix issues hurting inbox placement rates.

If you run email marketing campaigns, you know how essential it is to get your messages into the recipients’ inboxes.

But let’s be honest, great email deliverability seems like an impossible task to achieve with changing algorithms and all those spam filters in fierce competition for attention.

According to recent industry data, nearly 20% of permission-based emails never reach consumers’ inboxes because they’re filtered as spam or junk. For B2B SAAS companies running cold email campaigns, poor deliverability can cost thousands in lost opportunities, every undelivered email is a missed sale or partnership.

That’s what email deliverability audits are for: providing insights on how to take action or showing which methods work, which ones don’t, and how to make sure that emails go precisely to the primary inbox they need to be in.

Whether you’re experiencing declining open rates, rising bounce rates, or simply want to ensure your cold email campaigns reach decision-makers, a comprehensive deliverability audit is your first step toward inbox success.

In this guide, we will go through everything you should know while running an audit of email deliverability.

What is an email deliverability audit?

An email deliverability audit is a systematic review of all the factors that influence whether your emails successfully reach your recipients’ primary inbox — not just get accepted by their mail server.

It helps you understand if your messages are landing in inboxes or being flagged as spam and why. It looks into things like:

• Your sender reputation
• Authentication records (SPF, DKIM, DMARC)
• Bounce and complaint rates
• Engagement metrics like opens and clicks
• Spam triggers in your content or headers

By conducting an email deliverability audit, you can find hidden issues that hurt your campaign performance and take action to fix them — ensuring your email messages are seen.

Read more: How to Find + Troubleshoot Email Deliverability Issues

Why is email deliverability audit important?

Email deliverability is paramount to any email marketing campaign. Here is why:

First of all, bad deliverability completely ruins your ROI.

Think about the time, effort, and money that go into making fantastic email campaigns; if those emails do not even reach the recipient inboxes, your time, money, and efforts are completely wasted.

On the other hand, if you’re doing frequent audits and good deliverability, you can realize some serious benefits, which include:

• Improved inbox placement – Emails will more likely arrive at the primary inbox where they’re most likely to be seen and engaged.

• Higher open and click-through rates – If your emails are consistently hitting the inbox, more people are seeing and interacting with them.

• Improved sender reputation – When your engagement rates are high, email providers know you’re a sender they can trust, creating a positive feedback loop for future campaigns.

• Lower bounce rates and fewer spam complaints – By discovering and resolving issues before they get worse, you will not have many email bounces and complaints, which further enhances your reputation.

But what happens when you ignore deliverability?

The impact can be rather significant:

• Blacklisting – If a great number of your emails are reported as spam, you can find yourself on email blacklists, making it close to impossible to deliver your emails to the recipients.

• Reduced customer engagement – If your emails are always going to spam folders, your prospects never get your pitch delivered; therefore, over time, there will be reduced engagement.

• Lost revenue opportunities – If any of your emails are filtered out of the inbox, this is surely a lost chance to close a sale.

DIY vs. Expert: Should you hire a deliverability consultant?

Before diving into the audit process, you need to decide: should you conduct the audit yourself or hire a deliverability expert?

DIY email deliverability audit

Best for:

• Small to mid-sized SAAS companies (<100,000 emails/month)
• Teams with basic technical knowledge (can configure DNS records)
• Quarterly maintenance audits
• Budget-conscious startups

Pros:

• Cost-effective (tools like SmartReach.io offer built-in audit features)
• Learn your system inside out
• Quick turnaround (1-2 weeks)
• Control over implementation

Cons:

Requires technical expertise for DNS/authentication setup
Time-consuming for first-time auditors
May miss advanced issues
No expert guidance on complex problems

Hiring a deliverability expert

Best for:

• Enterprise companies (1M+ emails/month)
• Persistent blacklisting or severe reputation issues
• Complex multi-domain setups
• Teams lacking technical expertise

Pros:

• Professional expertise and experience
• Comprehensive analysis with detailed reports
• Faster issue resolution for complex problems
• Ongoing consultation and monitoring

Cons:

• Expensive ($2,000-$10,000+ per audit)
• Takes 2-4 weeks for a full audit
• Requires contract/commitment
• Implementation still requires your team’s effort

Our recommendation

Start with DIY audits quarterly using tools like SmartReach.io’s built-in deliverability monitoring. Hire an expert only if you encounter:

• Persistent blacklisting issues
• Sender scores below 70 (severe reputation damage)
• Deliverability drops >30% with no clear cause
• Enterprise-level complexity (multiple domains, high volume)

For most B2B SAAS teams, a DIY audit every 3-6 months is sufficient to maintain healthy deliverability.

How to perform an email deliverability audit: 8-step process

Now that you understand the importance of email deliverability audits, let’s dive into actually conducting one.

An email deliverability audit typically takes 1-2 weeks for DIY implementation or 2-4 weeks if you hire a professional consultant. The process involves checking technical authentication, analyzing sender reputation, reviewing email content, and testing inbox placement across major providers like Gmail, Outlook, and Yahoo.

We’ll break this down into 8 key steps that you can follow to ensure your emails are reaching their intended destinations.

1. Configure your technical setup

First things first, you need to make sure your email technical foundation is solid.

Here’s what you shall do, set up these three critical elements of email deliverability authentication protocols: SPF, DKIM, and DMARC.

• SPF is the Sender Policy Framework. Think of it like your guest list for email: it shows that host servers with IP addresses are allowed to send an email on your behalf, so spammers can’t pretend to be you.

• DKIM (Domain Key Identified Mail) is a system that places a digital signature in your emails. It proves that the email came from you and hasn’t been tampered with along the way.

• DMARC (Domain-based Message Authentication, Reporting, and Conformance) binds SPF and DKIM together. This informs a receiving server of the action to take if an email fails those checks: should it be rejected, or should it be put in the spam folder? These reports make it easier to be able to tell who’s trying to send emails pretending to be you.

Read more: Steps to authenticate SPF, DKIM, and DMARC for Google Workspace

Once these are in place, email service providers will be more likely to trust your emails and route them into the inbox.

Do note that setting these protocols is not a one-time setup.

You will need to check regularly that they are working correctly and update them in case you change email servers or add new sending domains.

2. Warm up your email accounts

Getting your email account warmed up is like slowly introducing yourself to a party rather than bursting in and yelling at everyone. 

Once you start sending emails from a new IP or domain, the process of building a good reputation with Internet Service Providers can take some time before you can send huge volumes of emails.

In theory, it’s easy: start small and gradually increase your volume over time. There’s an art to doing it right, though.

The best approach to warming up your email accounts is to send cold emails first to the most engaged prospects, people who have consistently opened and clicked your emails. These good engagements will enhance your credibility and reputation.

You can also resort to email warm-up tools that would make this process easier to automate. The warming-up will likely take 4-8 weeks, depending on how your send volume is and how it goes.

The idea is to convince the ISPs that you are a good guy sending diversified and relevant content.

If you are switching from an old IP to a new one, consider sending from both during the warm-up period.

If you see issues, ramp down. It’s better to go slow than to hurry and see your reputation ruined.

3. Craft high-quality & relevant email content

The quality and relevance of email content are extremely important. 

To do that, we would recommend segregating the lead list first.

That is, you need to divide your email prospects into different groups in terms of their interests, behaviors, or even demographics. After that, you can create content for each of these groups. 

So, let’s say, for example, you have a pet shop. In this case, you will not send the same email you sent to cat owners to dog owners.

More importantly, you want to personalize your email copies as much as possible.

You can mention your prospect’s name, company name, pain point, challenges, or any recent achievement.

Furthermore, we even recommend adding real value to your emails. It could be useful information, an exclusive offer, a personalized product proposal, or even happy hour.

Ask yourself, “If I received this email, would I be glad I opened it?”

Finally, ensure you aren’t degrading your email content with typical spam words like “free,” “guarantee”, or “click here”—these set off spam filters.

Last but not least, always make sure to follow a regular sending schedule, so your prospects get accustomed to your emails.

Just don’t send so often that people get annoyed and unsubscribe or mark you as spam.

Avoid Spam Trigger Content

While “spam trigger words” are often overblown, certain patterns do raise red flags for spam filters:

– Excessive capitalization: “FREE TRIAL NOW!!!” → “Start your free trial”
– Too many links: Limit to 3-5 relevant links per email
– Image-heavy emails: Maintain a 70:30 text-to-image ratio
– Suspicious attachments: Avoid .exe, .zip files in cold emails
– Misleading subject lines: Subject must match email body content

More important than avoiding specific words is maintaining strong engagement rates. If recipients consistently open and click your emails, ISPs will trust your content regardless of word choice.

4. Clean your email lead list frequently

Cleaning your email list is almost the same as cleaning your closet: you get rid of old contacts, reorganize active subscribers into order, and make room for new people who could be prospective customers.

It sounds counter-intuitive to remove subscribers, but a small and healthy list will work so much more effectively than an oversized and overgrown one.

To clean your lead list, you need to identify and remove invalid email addresses, meaning addresses for emails that have hard bounced—that is, the email account it was meant for no longer exists.

Keeping these on your list can hurt your sender’s reputation.

The second thing you should do is identify all of the role-based email addresses, such as “info@” or “support@,” and consider deleting those leads from your list since that’s usually an inbox that is shared by many and can contribute a lot to your spam complaints.

Next, check your analytics and see which prospects haven’t opened, or clicked in a while. You’ll want to launch a separate re-engagement campaign for these before removing them.

Remember, a clean list promotes better deliverability, higher engagement rates, and more precise metrics. It’s an ongoing process, but worth the trouble for your email outreach to be successful.

5. Track your inbox placement rate

Your inbox placement rate informs you about how many of your emails are arriving in the inbox of your leads, and not going to the spam box.

This rate is very important because it lets you know for sure how many of your emails are going to your subscribers’ inboxes.

A low inbox placement rate means many of your emails might go straight to the junk folder or be blocked.

To track this, you’ll need to use specialized tools like 250ok, Return Path, or GlockApps.

These will send test emails to a network of seed addresses across the spectrum of email providers and report back on just where all those emails landed.

Ideally, you should monitor the inbox placement rate regularly, and when you notice a sudden drop, you should pause all the campaigns to find out the issue.

Remember, a good inbox placement rate isn’t just about avoiding the spam folder.

Even if your emails are delivered, they might be going to a “Promotions” or “Updates” tab instead of the primary inbox.

While this is better than the spam folder, it can still impact your open rates.

Top inbox placement testing tools

Tool	Best For	Key Features	Pricing
GlockApps	Comprehensive testing	Tests across 20+ providers, spam score analysis	$49-199/mo
Mail-Tester	Quick spot checks	Free spam score check, authentication validation	Free
250ok	Enterprise monitoring	Real-time monitoring, reputation tracking	Custom
SmartReach.io	Cold email teams	Built-in deliverability checker, warmup automation	Included in plans
Litmus	Email marketers	Design testing + deliverability checks	$99-199/mo

Pro Tip: Use a combination of free tools (Mail-Tester for quick checks) and your cold email platform’s built-in features (like SmartReach.io’s deliverability monitoring) for cost-effective ongoing tracking.

6. Track sender score

Your sender score is like your credit score in the email world.

A rating that goes from 0 to 100, reflects the state of your email sender reputation.

The higher your score, the greater the chance your emails have of hitting the inbox.

It’s a score computed by considering many factors — from your bounce rates to spam complaints and sending volume, plus how much people are engaging with your emails.

You can check your sender score through places like SenderScore.org. Much like you would regularly check up on your credit score.

Generally, any score above 80 is pretty good.

So if your score is less than that, it’s time to take action.

Check out the factors that go into the score:

• Are you getting a great deal of spam complaints?
• Is your email bounce rate high?
• Are folks not engaging with your emails?

Remember, your sender score may differ on various ISPs.

You might have a brilliant score on Gmail and a lousy one on Outlook.

That is why you need to constantly check your score through different tools.

Suggested: 10 Tools To Check Sender Score (Free + Paid)

7. Monitor email bounce rates

Tracking your bounce rates is as important as tracking your inbox placement rate.

To the uninitiated, bounces are when your email can’t be delivered, and they come in two flavors – hard bounces and soft bounces.

Hard bounces are permanent failures. The reason may be that the email ID no longer exists or that the domain name is misspelled. You must remove hard bounces immediately from your list.

Soft bounces are transient. The prospect’s inbox could be full, or their server might be down. You can retry later, but if the soft bounces persist from the same address, remove it after a few tries.

A too-high bounce rate can be very tough on your sender’s reputation. It’s a red flag to the Internet Service Providers that you might be sending spam or using an old, uncleaned list.

So, you should always make sure that your bounce rate is less than 2%. If you are higher, then it is time to do some list cleaning.

Bounce rate benchmarks by industry

Understanding what constitutes a “good” bounce rate helps you set realistic goals:

– Excellent: <1% bounce rate (well-maintained list)
– Good: 1-2% bounce rate (acceptable for most campaigns)
– Warning: 2-5% bounce rate (needs immediate list cleaning)
– Critical: >5% bounce rate (risk of blacklisting, pause campaigns)

For cold email campaigns specifically, aim to keep your bounce rate under 3%. Any higher signals poor list quality to ISPs and can trigger spam filters even for valid recipients.

8. Measure email reputation

Your email reputation is the equivalent of a thorough health check on your email program.

It goes beyond the sender score to give granularity into how ISPs and prospects view your emails.

First of all, to measure your email reputation properly, you should check the complaint rate. This is the percentage of people who mark your emails as spam.

Even a small percentage can affect your reputation big time.

Ideally, your complaint rate must be lower than 0.1%. If it’s higher, you must reassess your content and sending practices.

Next, you want to monitor the email engagement rates. This is a matter of open rates and click-through rates, but it is also how many replies to or forward your emails.

High engagement will tell ISPs that your e-mails are wanted and valuable.

Most importantly, do not forget to check the quality of your outgoing IP addresses. If you are on a shared IP, you may be affected by the other sender’s reputation. 

For this, you can use Google Postmaster Tools and Microsoft SNDS, which provides real-time, direct feedback from major ISPs. These tools may give insight into your reputation that is provider-specific.

How often should you audit email deliverability?

Regular email deliverability audits are essential for maintaining healthy inbox placement rates. Here’s when and how often to conduct audits:

Recommended audit frequency

Quarterly audits (Every 3 Months):

• Best for: Active cold email campaigns, ongoing lead generation
• What to check: Sender score, bounce rates, spam complaints, inbox placement tests
• Time required: 2-4 hours using automated tools

Bi-Annual audits (Every 6 Months):

• Best for: Occasional email marketers, low-volume senders
• What to check: Full technical setup review, authentication protocols, list health
• Time required: 1-2 days for comprehensive review

Immediate audits (When issues arise):

Conduct an emergency audit immediately if you notice:

• Open rates drop >20% suddenly (e.g., from 40% to 20%)
• Bounce rates spike above 5%
• Sender score drops below 80
• Multiple blacklist notifications
• Significant spam complaints (>0.1% of sends)

New Domain/IP Audits

If you’re launching a new sending domain or IP address:

• Week 2: Initial check after warm-up starts
• Week 4: Mid-warm-up audit (adjust volume if needed)
• Week 8: Post-warm-up comprehensive audit
• Quarterly: Ongoing maintenance audits

Pre-Campaign Audits

For high-stakes campaigns (product launches, investor outreach, event invitations):

• Audit 1-2 weeks before major send
• Fix any issues discovered
• Re-test inbox placement just before launch
• Monitor closely during first 48 hours of campaign

Post-Campaign Reviews

After major campaigns, review within 7 days:

• Deliverability impact assessment
• Engagement rate analysis
• Sender reputation changes
• Lessons learned for next campaign

Bottom Line: Most B2B SAAS teams should conduct quarterly DIY audits using tools like SmartReach.io, plus immediate spot checks whenever metrics decline. This cadence catches issues early without over-auditing.

Conclusion

Running a comprehensive email deliverability audit every 3-6 months is one of the most impactful actions you can take to improve your cold email campaign performance. By systematically checking your technical setup, sender reputation, list quality, and inbox placement, you’ll catch issues before they escalate into blacklisting or reputation damage.

Keeping your emails out of the spam folder is not about avoiding some number of magic words or adhering to major rules; it is about maintaining decorum in your list and maintaining a good reputation as an email sender.

Key takeaways from this guide:

– Conduct DIY audits quarterly using tools like SmartReach.io’s built-in deliverability monitoring
– Maintain sender scores above 80 (ideally 90+) for optimal inbox placement
– Keep bounce rates under 2% and spam complaints below 0.1%
– Properly configure SPF, DKIM, and DMARC authentication protocols
– Monitor inbox placement rates across Gmail, Outlook, and Yahoo regularly
– Audit immediately if open rates drop >20% or bounce rates spike above 5%

If you stick to these critical practices, do not doubt that you’ll see your emails landing in the primary inboxes of your prospects and greatly increasing the results of your outreach.

For the best email deliverability, rely on a cold email software like SmartReach.io that provides built-in tools for good email deliverability and inbox placements.

Try SmartReach.io for FREE. (14-day free trial – no credit cards required)

FAQs on email deliverability audit

Q: What is an email deliverability audit?

A: An email deliverability audit is a systematic review of factors determining whether emails reach primary inboxes or spam folders. It examines sender reputation, authentication protocols (SPF/DKIM/DMARC), bounce rates, and engagement metrics to identify issues like blacklisting or misconfigured settings that hurt inbox placement.

Q: How long does an email deliverability audit take?

A: A DIY audit takes 1-2 weeks using tools like SmartReach.io or MxToolbox, covering authentication checks, sender reputation analysis, and inbox placement testing. Professional consultants need 2-4 weeks for comprehensive audits with detailed reports. Implementation of fixes requires an additional 2-4 weeks depending on severity.

Q: Can I do an email deliverability audit myself or should I hire an expert?

A: You can DIY if you have basic technical knowledge and send under 100,000 emails monthly—platforms like SmartReach.io make self-auditing cost-effective. Hire experts for high volumes (1M+ monthly), complex workflows, persistent blacklisting, or if your team lacks SPF/DKIM/DMARC expertise.

Q: How often should I audit email deliverability?

A: Conduct comprehensive audits every 3-6 months for ongoing campaigns, or immediately when open rates decline, bounce rates exceed 2%, or spam complaints surpass 0.1%. Audit before major sends like Q4 outreach or Q1 planning. New domains need audits after warm-up (4-8 weeks) plus monthly monitoring initially.

Q: What tools do I need for an email deliverability audit?

A: Essential tools include sender reputation checkers (SenderScore.org), authentication validators (MxToolbox), blacklist checkers (Spamhaus), and inbox placement testers (GlockApps). SAAS platforms like SmartReach.io offer built-in monitoring, while Google Postmaster provides Gmail insights. Email verifiers like NeverBounce clean invalid addresses.

Q: What is a good sender score?

A: Good sender scores range from 80-100 on Return Path’s scale. Scores above 90 indicate excellent deliverability, 80-89 is acceptable but needs monitoring, and below 70 signals serious reputation issues causing spam filtering. Your score reflects bounce rates, spam complaints, and engagement across your IP and domain.

Q: How do I check if my emails are going to spam?

A: Use inbox placement tools like GlockApps or SmartReach.io’s checker to test across Gmail, Outlook, and Yahoo. Alternatively, send tests to your own accounts on multiple providers and check Primary, Promotions, and Spam folders. Declining open rates below 20% often indicate spam filtering.

Q: What’s the difference between email delivery and email deliverability?

A: Email delivery means your message reached the recipient’s mail server without bouncing, it was accepted. Email deliverability measures whether it landed in the primary inbox versus spam or promotions. You can have 100% delivery but poor deliverability if emails reach spam folders instead of inboxes.