How to Test Email Deliverability

Email is one of the most effective marketing tools out there, but even the most expertly-crafted emails are next to useless unless they make it to the inbox. To ensure that your marketing effort doesn’t go to waste, you need to test email deliverability on a regular basis, and we explain how to do just that in this article.

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What Is Email Deliverability?

Before we explain how to test email deliverability, we need to first clarify what the term actually means because there’s a lot of confusion surrounding it.

To start with, there’s a difference between “deliverability” and “delivery.” While the latter is used to describe whether or not a recipient’s server accepted a marketing message, the former is a marketing term used to distinguish emails that have made it to the inbox from those that haven’t.

Technical issues, such as unstable connection or server overload, are responsible for most email delivery issues. The good news is that email delivery tests are usually unnecessary because mail servers automatically report delivery errors on their own. On the other hand, problems with email deliverability stem from poor sender reputation score, bad content quality, and unclean mailing lists containing incorrect addresses, among other things.

Although it takes some time to improve email deliverability, performing a test is a quick process that takes just a few minutes from start to finish.

When Test Email Deliverability?

According to data published by EmailToolTester, the average deliverability rate hovers around 80%. As such, anything above this number is considered to be a good email deliverability rate, while anything lower than 80% should prompt an email deliverability test.

Additionally, it’s always a good idea to perform testing before the start of any email marketing campaign to maximize its effectiveness. If the campaign has a longer duration, consider performing further tests at regular intervals.

There are several ways to estimate deliverability, and the best testing tools available combine them together into a single straightforward process:

Top Email Deliverability Testing Tools

The good news is that marketers don’t have to worry about too much the technical side of things since they can quickly and easily check email deliverability using the following tools.


Developed by geeky email software engineers to be cheap, simple, and efficient, is a no-frills tool that lets you test email deliverability in one simple step. That’s right! All you need to do to obtain an accurate deliverability score is to send a message to the provided address. This email address tester app will then tell you what SpamAssassin, a spam checker developed by the Apache Software Foundation, thinks about your message. You will also learn if your mail account is blacklisted or not fully authenticated, among other things. With the free version of, you can perform up to 3 tests per day, which should be enough to learn how the tool works.

2. MxToolbox

MxToolbox is a well-known name when it comes to email testing and monitoring, and its tool analyzes the headers, the blacklist reputation of your outbound IP address, and your SPF records. It then generates a comprehensive deliverability report, providing you with a wealth of useful information that you can closely analyze and use to improve the performance of your marketing campaigns. Free users are limited to one free monitor with access to the top 30 blacklists, so consider upgrading to the paid plan if you’re interested in access to multiple monitors and more blacklists.

3. Spamcheck by Postmark

Spamcheck by Postmark is an easy-to-use online tool that lets you instantly check the SpamAssassin spam score of your messages. As we’ve already mentioned, SpamAssassin is an open source spam checker that uses a variety of spam-detection techniques to separate spam from legitimate emails. It’s used by many service providers, so knowing how it sees your messages is extremely helpful in determining their deliverability. What’s great about Spamcheck by Postmark is the fact that you can simply paste a message including its full headers and content—no need to send it anywhere.

4. GlockApps

With GlockApps, you can perform virtually all checks marketers use to maximize inbox deliverability. This includes sending your IP and domain information against more than 50 industry blacklists, tracking if your content or IP is blocked by Gmail, Yahoo!, or other ISPs. All MailChimp users will appreciate that GlockApps lets them easily test their marketing campaigns directly from its website thanks to the integration between the two services. Free users get 3 detailed reports, and they can then choose between annual, monthly, or on a per-test basis plans.

5. SendForensics

If you’re interested in generating detailed deliverability reports, then you should check out SendForensics. This tried-and-tested tool highlights the issues that send your emails to the spam folder by performing pre-emptive email deliverability testing and real time scoring for live sends. You can compare your rate with industry and regional benchmarks to know how well you’re doing and set alerts to quickly discover emerging issues before they become huge problems that can potentially ruin your entire marketing campaign.


Spam accounts for the majority of all email traffic, so it makes perfect sense for service providers to aggressively protect their users from unwanted messages. Unfortunately, no spam protection is perfect, so it’s not uncommon for legitimate emails to end up in the spam folder. To ensure that your marketing effort doesn’t go to waste, you need to check email deliverability from time to time using the tools listed in this article.

How to Test Email Deliverability - FAQs

1. How do you test email deliverability?

It can be easily tested using one of the many available email deliverability tools, most of which can be used for free with certain limitations.

2. How do you know if an email is delivered?

Unless either your or the recipient’s mail server generates an error message, then the message has most likely been delivered—no need to perform an email delivery test.

3. How do I check email deliverability in Salesforce?

Emails sent through Salesforce originate from one of a number of possible Salesforce IP addresses, which may be blocked by the recipient. To check email deliverability in Salesforce, follow these instructions.

4. How can I test an email without sending it?

There are tools that let you test the content of your message against spam filters without sending it. You can also test the configuration of your mail server to verify that it’s behaving the way it’s supposed to behave.

Clean Email Team Updated on May 8, 2022