Email & SMS

The Ultimate List of Email Testing Tools for 2020

By Tinuiti Team

Emails are a valuable communication tool that helps you connect with customers and prospects. But an email campaign is a deceptively high-stakes game. You can only send each email to each person once–there are no do-overs. If you screw up, everyone will be able to see it, and you’ll be lucky if they stick around for the next attempt. 

By using proper email testing tools, you can minimize the risk of mistakes and increase your chances of getting the right message across to the right people. 

“The truth is only 31% of brands test a majority of their emails and 39% don’t test their emails at all. Why? Because it’s easier not to. While we can understand the hesitation, email testing is still the best way to continually refine your email campaign strategy over time.”

–  Jenny Tran, Strategist, CRM & Email at Tinuiti


jenny tran


There are a lot of factors that affect an email campaign’s success; from deliverability to subject line to the quality of your email list. Because of that, there are many email testing tools available to choose from–each with their own specialties and characteristics. So we’ve assembled a list of the best options for each purpose.

For your convenience, we’ve categorized the list based on the tool’s primary function. 

Email Previewing and HTML Validation

You check yourself in the mirror before you go out of the house because you want to make sure you look good, right? The same thing should apply to your emails. 

Email previewing tools let you test how your email will look in various browsers, email clients, and devices. HTML validation tools do the same thing, except they focus on checking the actual HTML, XHTML or CSS code for errors. 

1. Litmus

Free Trial: 7 days

Pricing: Pay per month

Best used for: Enterprise users that can afford Plus tier and higher.

Description: Litmus is at the top of many websites’ lists of email testing tools, and for good reason. Its email preview feature alone is at the top of its class. Set up a test email, and Litmus will show you what it will look like when viewed in literally dozens of different formats. 

Litmus’ basic version already has the ability to preview emails, but you have to sign up for the higher tiers in order to really maximize the platform’s potential. Higher tiers expand both Litmus’ email testing capabilities and its ability to segment and send users. 

2. EmailMarkup Tester by Google

Free Trial: None

Pricing: Free

Best used for: Developers or marketers who need a quick way to check Schema markups

Description: For those of you unfamiliar with the term, email markups allow you to put calls to action like “RSVP” and “Complete purchase” right in your email’s subject line. The email recipient doesn’t even have to open the email to convert!  

Google’s EmailMarkup Tester lets you quickly and easily test the validity of your code without you having to send a test message. It’s fast, it’s convenient, and it’s free.

3. Accessible-Email

Free Trial: None

Pricing: Free

Best used for: Developers or marketers that need to check code for accessibility

Description: Accessibility allows people with disabilities to more easily access electronic information–including your emails. More marketers are recognizing the need to make their marketing more accessible to those who need it, and so this is a good email testing tool to include in your QA process. 


Free Trial: Free tier

Pricing: Pay per month

Best used for: Good for small, medium, or large-sized marketing or development teams.

Description: Mailtrap is a service that helps you reliably isolate test emails from production emails and completely eliminates the chance of a test email landing in an actual customer’s inbox. It works by associating each of your SMTP servers with a specific Mailtrap inbox. Once it’s in the Mailtrap inbox, you can perform whatever rendering or HTML validation tests you want. 

All features are unlocked at the free tier, but it’s only limited to a small number of emails a month and 1 inbox. The higher your tier, the more tests you run and the more inboxes you can use. 

Subscriber Verification

You want to make sure your emails are going out to real people, so many marketers use subscriber verification tools to check their lists. 


Free Trial: Free 100 credits

Pricing: Two pricing models

* Credits do not expire

Best used for: Marketing teams that have large email lists.

Description: is one of the more popular items on this list thanks to the combination of affordable pricing and consistent performance. It can reliably find duplicates and mistyped domain names, and will even check emails against known blacklist databases. 

6. Pabbly

Free Trial: Free signup, no trial

Pricing: Pay per email

* Credits do not expire

Best used for: Good for marketing teams of all sizes

Description: Pabbly claims to have the highest deliverability success rate in the industry: 98%. A large part of this is due to their “slow” approach to email verification. As they describe it, pinging a recipient’s mail server too fast can result in denied requests or erroneous data. So they ping mail servers at a slower rate to simulate actual human behavior. The result? Incredibly accurate verification results. 

Sender Reputation

Your email might get sent to spam for a number of reasons, and one of those is the sender’s reputation. These tools will check for any red flags that might cause your email to be rejected. 

7. Reputation Authority

Free Trial: None

Pricing: Free

Best used for: Marketers that need to check their domain or IP’s reputation score

Description: Reputation Authority is a free email testing tool created by Watchguard, an online security technology company. It’s pretty simple. Enter any domain name or IP address in the provided field, and it will give you all the IP addresses associated with that domain and their matching reputation, with ratios of “good” and “bad” mail originating from that domain. 

8. Spamcheck from Postmark

Free Trial: None

Pricing: Free

Best used for: Developers or creatives checking the spam score of emails before sending

Description: Spamcheck is a free tool from email platform Postmark that instantly checks your email’s potential spam score. It’s a very convenient tool to use that doesn’t require any signups or login information. Simply copy your email’s HTML code into the provided text box, and it will instantly generate a spam rating. 


Sometimes verifying your sender reputation isn’t enough to get your emails through the spam filter. There may be other issues at play. Deliverability tools help you suss out what those issues are.

9. Mailgun

Free Trial: 3 months

Pricing: Pay per month

Best used for: Enterprises or agencies that send large volumes of emails

Description: Mailgun is an all-in-one email marketing tool that combines email sending, marketing and analytics functions into the same platform. Mailgun is notable for its strong validation and deliverability testing tools, which is why it’s on this list. In addition to the tools themselves, Mailgun also offers deliverability services to guide you and help you adopt more successful email marketing processes.

10. SendForensics

Free Trial: 1 free test

Pricing: Pay per month

Package A – $49/mo

Package B – $79/mo

Package C – $199/mo

Package D – $349/mo

Best used for: Enterprise marketers

Description: SendForensics is a top-tier email deliverability and security testing tool that helps enterprise marketers protect their email reputation. SendForensics allows marketers to test their emails for both delivery and engagement. Enterprise users can further use the tool to test network deliverability, counterfeit emails and DMARC compliance.

Subject Line Testing

A good subject line can make the difference between a successful email campaign and a waste of resources. It can be hard to tell what will work and what won’t. Fortunately, there are tools available that take a data-driven approach to creating a great email subject line.

11. SendCheckIt

Free Trial: Free

Pricing: Free

Best used for: Anyone

Description: SendCheckIt is a deceptively simple email subject line testing tool. All you need to do is enter your proposed subject line, and SendCheckIt will email you the test results. The report itself is very comprehensive, including things like reading grade level, scannability, sentiment analysis, and spam potential. 

12. HeadlineAnalyzer from CoSchedule

Free Trial: Free

Pricing: Free

Best used for: Anyone

Description: CoSchedule is a project management platform for marketers that released a free tool to analyze blog headlines. But this tool is so good that marketers are using it for more than just content–it’s also effective at analyzing email subject lines. The two formats share the same basic need: attract viewer attention. Try it yourself and see how well it works for you.

Pro-tip: Don’t skip the testing phase whenever you run an email campaign. Instead, make room in your production schedule for as many tests as you can afford. It will increase your email’s chances of getting to your audience’s inbox, catching their attention, and converting. Your bottom line will thank you.


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