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Lost in a Junk Folder Nightmare? Escape (and Never Worry Again) with an Email Deliverability Audit


We send email campaigns to prompt recipients to take a specific action—to start using a new feature in our app, register for a webinar, or make a purchase from our online store. All our efforts are wasted when messages go to spam folders. That’s why it’s crucial to track the performance of your campaigns and find both technical and marketing ways to improve the results.

An email deliverability audit is an effective technical method to increase the open rate.

In this article, I will talk about:

DIY or outsource: Who should do the audit?

A deliverability audit is a complex process with a variety of ins and outs. Therefore, the first question is whether you should hire an expert or do it yourself (DIY).

In general, if you have a large volume of messages and a sophisticated email workflow, it’s recommended to outsource the audit. However, expert help can also come in handy for smaller teams to get insights into their email sending processes.

Here are the pros and cons of an outsourced vs. in-house email deliverability audit:

Hiring an expertIn-house audit
  • One-off cost
  • Learning best practices
  • Getting exact time estimation
  • Results guarantee
  • Can be quicker
  • Gaining own expertise
  • Can be cheaper
  • Uncertainty in terms of outcomes and process
  • Can be more expensive
  • No clear budget and time estimation
  • No results guarantee
  • Can take longer


Usually, the full audit is performed for a single isolated campaign to avoid judging based on average score of all campaigns because deliverability depends on a whole list of factors:

  • Technical setup (SMTP server, IP, email authentication, etc.)
  • Email content (and no, I don’t mean spam trigger words)
  • Contact list—are you using problematic acquisition sources?
  • Sender’s behavior (how often you send emails, how you segment your recipients, etc.)

When performed by a deliverability expert, an audit typically takes up to two weeks. You should receive a report that describes tests that were run and issues found, with a list of tools and screenshots, as well as recommendations on how you can increase your email deliverability. But you won’t know if any of it will actually help or not until you put the report to use, after your contract with the expert has ended.

You can make an audit yourself, using the same tools and approaches, but you will need to interpret the results and create an implementation plan yourself. You’ll also have to pay for the different tools yourself as well as spend time and effort learning them. But you can keep an ongoing watch over your email deliverability and make adjustments as you go along.

If you decide to hire an expert, you can start by checking with your email sending provider to see if they offer this kind of service. There are also companies that offer both deliverability testing tools and consulting services. Alternatively, you can search for consultants on Upwork, LinkedIn, or Reddit communities. Follow your needs, reviews from real clients, the structure of an offer, and results guarantee.

How to perform an email deliverability audit

Whether you decide to do it yourself or hire an expert, the process and outcome should be very similar.

1. Define your goals

Specify what you expect from the audit. Do you already know your deliverability issues and need guidelines on how to fix them? Do you have doubts about the reliability of your sending infrastructure? Or do you just watch the low open rate and want to find a way to improve it?

2. Select metrics and the tools to assess them

You need to understand which email aspects will be tested: sending domain, authentication, IP and reputation, blocklist and spam check, email content, and list validation.

Then, select the tools you’ll need to assess those metrics. There are a bunch of deliverability testing tools you can use, both free and paid, that give you an overall deliverability review, show you your sender reputation, validate your contact list, or analyze email performance.

I recommend starting with complex email deliverability checks and then inspecting specific aspects.


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3. Create a checklist

You can use spreadsheets or any project management tool you prefer to document metrics, tools you need, results of the audit, and further action points. This is a great way to keep you on track and make sure you’re not missing anything critical.

4. Run your deliverability tests

Now you’re ready to do the actual audit! Evaluate each of the deliverability elements and metrics you’d like to measure according to your checklist and add the results. What are you doing well? What needs improvement? Your email tools should give you an idea of what’s considered good or bad.

5. Prioritize needed fixes

So, your results show you’ve got quite a few things you can improve. What now? Start with the musts—the most important issues that can bring the most valuable results. Then collect low-hanging fruits, and make fixes that are easy and fast to implement.

An impact-effort or action priority matrix is a great way to visualize your quick wins, major projects, and what may not be worth the effort.

impact effort action priority matrix
Source: Mind Tools

6. Prepare the implementation plan

The next step? Create an action plan that contains the needed fixes, ways of applying them, who’s responsible for them, and deadlines. A good email remediation plan not only helps you cool the burn but also ensures deliverability success moving forward.

Maintain great deliverability with email best practices

When you work with a deliverability expert, they will explain the analysis results and provide actionable recommendations on what should be improved. When you analyze email deliverability with your own resources, you make your own conclusions.

While there are technical improvements to consider, here are a few tips that can also help you improve your email performance—a big factor in getting your emails delivered to the inbox.

Email content

The more elements you include in your message, the higher your chances of ending up in spam. But keep in mind the email clients your subscribers use and how those inbox providers may weigh different factors and filter emails. In general, consider the following:

  • Reduce the number of images and try to reach a live-text-to-image ratio of 70:30.
  • Reduce HTML file size to keep email data being received from 15 KB to 100 KB.
  • Avoid adding too many links since that can appear spammy. It is recommended to have less than five, but you should test your email before sending it to check how links affect your sending reputation.

Sender behavior

As an email sender, what behaviors do you need to adopt? Here are some suggestions:

Such tips will definitely boost your sales and marketing efforts. 😉

Make it to the inbox—not the spam folder

The most important part of an email deliverability audit is analyzing its results and implementing changes. The main goal is to increase email deliverability so that more people can receive, engage with, and convert from your emails!

In the end, you should clearly understand which aspects of your sending infrastructure, your behavior as a sender, and content details have the most impact on the delivery and performance of your campaigns. Implement these insights in every new email, test your emails thoroughly before sending, and iterate on changes to achieve meaningful results.

If you performed an audit yourself and couldn’t find the reasons for bad email performance, it may make sense to seek an expert’s help. Sending emails is a difficult process, with many puzzling elements and dependencies. That’s why it requires constant checkups and improvements.

Good luck with your audit, and happy sending!

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Andriy Zapisotskyi is a Growth Manager at Mailtrap, a product that helps people inspect and debug emails before sending them to real users. He has over 5 years of experience in the field of marketing & product. Andriy loves to network with people. Running is his hobby and he enjoys discovering new places. Connect with Andriy on LinkedIn or Facebook and share your feedback on this article.

Andriy Zapisotskyi

Andriy Zapisotskyi

Andriy Zapisotskyi was a Growth Manager at Mailtrap