When sending out cold emails (deliverability), you anticipate that the recipient will open the email and take action. But what if your emails never reach their inbox? Instead, they get stuck in the spam folder, or worse, a black hole. This disappointing scenario is all too common in cold emailing. The good news is that you can avoid these frustrating situations with proper email infrastructure. Email testing tools are an essential component of email infrastructure that helps you achieve flawless email delivery by identifying issues before you send out your cold emails. This blog will explore the importance of email testing tools, how they work, and the top options to help you optimize your cold emails for delivery, content, and engagement.

Inframail’s email infrastructure solution can help you achieve your goals for cold emailing. With Inframail, you can optimize every message for accuracy and engagement to ensure your emails reach their intended destination.

Table of Content

• What are Email Testing Tools & Why Use Them

• 30 Email Testing Tools for Accurate, Engaging Email Campaigns

• What Should You Look for In Email Testing Tools?

• Start Buying Domains Now and Setup Your Email Infrastructure Today

What are Email Testing Tools & Why Use Them

Email testing tools analyze your email for problems before you send it. They help you catch issues affecting your: 

• Deliverability

• Open rates

• Click rates

Email testing tools can improve campaign performance by ensuring your messages reach the right audience, appear as intended across different platforms, and avoid spam filters. Without these tools, you risk sending emails that won’t engage your subscribers.  

The Cost of Not Testing Your Emails

Recent stats show email ROI is $36 for every $1 spent. Spoiler alert: This isn’t true for everyone, especially those who neglect email testing tools.

Let’s say your marketing team emails 15,000 trial users who may want your product’s annual plan, which costs $504. At a 30% open rate, you’ll have 4,500 potential customers. Unfortunately, because your team didn’t test the email, they discovered it didn’t optimally display for your Outlook clients. If 10% of my trial users use Outlook, that means there are email rendering issues for 450 people. Factor in a 30% conversion rate, leaving you with 135 potential lost customers who have yet to click my call to action (CTA).

Put simply, you lost $68,040 (135 x $504) in potential revenue by not testing your email. Avoiding unexpected rendering problems is one area where email testing tools shine. When you test your emails, you also prevent issues with grammar and spelling, broken email design, image display, and the dreaded spam trap, which hampers email deliverability. 

Who Needs Email Testing Tools? 

If you use email marketing to connect with subscribers, you need email testing tools. It doesn’t matter if you’re: 

• A small business

• A SaaS company

• A large enterprise

You can’t afford to send poorly performing emails. Email testing tools ensure your emails are ready for the inbox so you can boost campaign performance and your bottom line. 

Types of Email Testing Tools

If you’re searching for the correct email testing tool, you probably have a specific problem in mind. You may want to optimize emails for better performance, ensure HTML email campaigns display correctly, or test factors related to email deliverability. 

1. Email Address Validation

Let’s start at the beginning of the email customer journey: the point of signup. That magical moment when a new subscriber permits you to email them. They’ll often opt-in through a form on your website. But what happens if they’re so excited to join your list (hey, it could happen) that they accidentally type Gnail.com instead of Gmail.com? There may also be people who just want to get their hands on that free download and use fake contact information or disposable email addresses. Email testing tools that can help prevent lousy contact data from landing on your list are email address validation or verification tools.

An email validation service determines whether an address is actual by testing to see if it can be reached. Some solutions validate emails at signup and those that verify contacts on your entire list. That’s needed, too – because people abandon personal email accounts, graduate from college, and change jobs, leaving old addresses behind. 

Why It’s Important

Besides the obvious reason that sending messages to a non-existent contact is a waste, there are other important reasons to conduct email validation. The biggest relates to your sender reputation and deliverability.

Since there’s no one on the receiving end of an invalid email address, bad contact data could drag down your email engagement rates. Invalid emails also lead to high bounce rates, which is another factor that can hurt deliverability. Mailbox providers take notice of low engagement and bounce rates, like: 

• Gmail

• Yahoo

• Outlook 

Avoiding Spam Traps: How Double Opt-In Can Improve Email Deliverability

The most dangerous of all are spam traps. Sometimes, abandoned email accounts are recycled to catch spammers. If you send to one of these recycled spam traps, mailbox providers may filter your messages to junk or add you to a blocklist.

One way to avoid email verification pitfalls is to implement a double opt-in, which asks new contacts to confirm their intent to sign up. You don’t add them to your list unless they click the link in a confirmation email. 

Who Needs This Type of Email Testing Tool?

If you’re a bulk email sender with a list that constantly grows with contact data from new customers and prospects, email validation is vital to good list hygiene. Verifying new contacts at sign-up helps keep your list clean, but you should also periodically check your entire list. 

2. HTML Email Previews

Once upon a time, there was a digital marketer who was blissfully unaware that while his emails looked great inside a popular ESP’s editor, they rendered like hot garbage in some of the most popular email clients. (This is a true story about me.)

Most email marketing software shows you how your campaign looks on mobile and desktop, but the real problems come with how email clients render HTML and CSS. Email rendering differs depending on the inbox provider/client. To get the whole picture, we always suggest visiting CanIEmail.com.

Desktop versions of Outlook, for example, could be more problematic. But Gmail and other providers have their issues too. Even though a new Outlook is coming in 2024 that will fix some issues, the old versions aren’t disappearing just yet. Email previews are screenshots from inside actual inboxes showing how an HTML email campaign renders in different clients, devices, and operating systems. These previews help senders find and fix problems like random white lines in Outlook or rendering issues with dark-mode emails. 

Why It’s Important

Brands want their email campaigns to reach inboxes looking as perfect as possible. When emails show up with broken layouts, they reflect poorly on the brand. Sometimes, the way campaigns are displayed makes emails unreadable. So, rendering inconsistencies can also reduce email engagement. 

Who Needs This Type of Email Testing Tool?

Senders with teams that include an in-house email developer who codes campaigns from scratch will almost always need this type of email testing. Email previews are also an essential test for digital agencies and freelancers specializing in email marketing.

Sinch Mailjet’s report, The Path to Email Engagement 2024, found that 71.5% of global consumers check their inbox on a mobile device. So, emails must be responsive to look and function correctly on smartphones. Mobile device previews help you catch problems.

Testing mobile email clients: Email previews from Sinch Email on Acid include more than 100 popular clients and live devices, including dark mode previews. Senders can tailor their email testing profiles for the inboxes that matter most. There are only a couple of players in the email preview game. We won’t mention our competitor, but their name rhymes with Spit-Bus. (Okay, it’s Litmus.) If you’re using a marketing platform that already provides email previews, there’s a good chance they’re using an API to white-label one of our services. 

3. Email Quality Assurance Testing

Email quality assurance (QA) is a more all-encompassing way to test email campaigns. While rendering issues are one of the biggest challenges of email development, there are many other things marketing teams should double-check before hitting the send button. There are the little things like typos and accidental profanities (because shit happens). There are also more significant problems like broken links, email accessibility, and blocklists. 

Once your campaign reaches inboxes, there’s no taking things back. Some teams use an email marketing checklist for quality assurance. The problem is that if this process is primarily manual, it leaves room for human error. An automated checklist creates a much more dependable, consistent workflow for pre-send email testing.

Why It’s Important

While email marketing delivers a high return on investment (ROI), your campaigns must be optimized for every inbox and subscriber to get the most out of each campaign.

Customers can’t convert if broken links fail to take them to your landing pages. Accessibility issues could make the text unreadable or mobile email CTA buttons untappable. Mistakes in an email marketing campaign do more than damage your brand reputation. Failure to conduct email quality assurance testing also reduces the email channel's revenue. 

Who Needs This Type of Email Testing Tool?

Whether you’re a recognizable brand or a smaller online store, you need to conduct pre-send testing for quality assurance if you rely on email to drum up business and drive customers to your website. 

4. Email A/B Testing

While email validation and previews are important tests before a campaign launches, another type of testing helps senders optimize for performance metrics such as opens and clicks.

Email A/B testing (split testing) lets marketing teams experiment with different campaign elements to discover the most effective. Subject line testing is just one of many experiments. For example, you find out if subject line A gets a higher open rate than subject line B. You could test CTA button placement, color, or copy. The imagery, headlines, messaging, and offers in your emails are also things to A/B test. 

Why It’s Important

The purpose of A/B testing is optimizing email design and copy in a way that resonates with your list so you drive email engagement. While you may have opinions about what will work, opinions can be wrong. Even so-called best practices may not be the approach that delivers the best results.

The only way to know for sure is to A/B test email campaigns. The winning variable will often surprise you. The marketing mantra “Always Be Testing” (ABT) exists. 

Who Needs This Type of Email Testing Tool?

Any email marketer who wants to improve campaign performance and better understand their subscribers should use A/B testing.

Many ESPs will include email testing tools like this as part of the platform. That includes Sinch Mailjet A/B testing, where you can define specific criteria for different tests depending on the metric you want to improve. With Mailjet, you can test up to 10 versions of an email campaign at once. 

5. Inbox Placement/Spam Testing

The fifth and final example on our list of email testing tools helps senders avoid one of the most dreaded destinations in digital marketing: the spam folder. Inbox placement refers to your ability to reach recipients’ inboxes rather than being filtered into spam or rejected by receiving mail servers. Inbox placement may also be called seed testing or spam testing tools.

The term seed testing is used because test emails are sent to a unique set of email addresses known as seed mailboxes. The seed list does not contain any real contacts. The addresses exist to generate a report on inbox placement. It shows the sender if a mailbox provider will likely let a message: 

• Reach the inbox

• Send it to spam

• Block it altogether

A good inbox placement report tells you where emails are likely to land. It also helps senders identify and fix specific deliverability issues, including: 

• Problems with email headers

• Authentication protocols

• Many other possibilities

Why It’s Important

New requirements from Gmail and Yahoo in 2024 have many senders paying closer attention to their deliverability. Sinch Mailgun’s Email and Customer Experience 2024 report found that more than 72% of consumers have a Gmail account, while more than 20% use Yahoo Mail. So, if you want to reach people, you’ve got to follow the new requirements.

Understanding how these providers filter your emails helps you catch deliverability issues immediately so they can be addressed. With the right inbox placement testing tool, you’ll get an accurate deliverability estimation before your emails go out to recipients. 

Who Needs This Type of Email Testing Tool?

Some emails are more important than others. For example, if your business relies on transactional emails to keep customers satisfied and business running smoothly, then the deliverability of those messages is crucial. You don’t ever want transactional emails landing in spam. Promotional emails can be significant, too – especially at certain times of the year, such as Black Friday and Cyber Monday. 

Related Reading

• Automated Lead Generation
• Email Prospecting
• How to Generate B2B Leads
• How to Warm Up Email Domain
• How Many Emails Can You Send Before Considered Spam
• Best Time to Send Cold Emails
• How to Cold Email
• Best Cold Email Templates B2B
• Email Outreach Best Practices
• Email Outreach Strategy

30 Email Testing Tools for Accurate, Engaging Email Campaigns

Sure! Here’s an organized, detailed list of the best email testing tools. 

1. Inframail

At Inframail, we are revolutionizing cold email infrastructure with unlimited inboxes at a flat rate. We provide: 

• Microsoft-backed deliverability

• Dedicated IP addresses

• Automated technical setup 

 It helps: 

• Agencies

• Recruiters

• Sales development representatives 

Our service boasts automated: 

• SPF

• DKIM

• DMARC setup

Unlike traditional providers that charge per inbox and leave you wrestling with technical configurations, Inframail streamlines the entire process. We handle the complex infrastructure setup while you focus on reaching more prospects. 

InfraMail provides the robust email infrastructure you need without the usual technical headaches and per-inbox costs, whether you're an: 

• Agency looking to scale outreach

• A recruiter connecting with candidates

• An SDR driving sales

Start buying domains now and set up your email infrastructure today!

2. Stripo

Stripo is an email design platform that allows teams to design responsive emails with little or no HTML skills required. It has a comprehensive drag-and-drop editor, and basic blocks allow users to create real-time content with no coding skills. Stripo was one of the first email builders to implement AMP for Email technology. Stripo will enable you to reuse and save email modules across different email campaigns. It comes with:

• Automated processes

• Custom modules

• Libraries

• Host of personalizations, like the ability to embed custom HTML code to create interactive elements. 

It provides users with over 1000 free, ready-to-use responsive email templates that are mobile optimized. Stripo comes with over 100,000 stock images and the opportunity to personalize and export emails and track conversions thereafter. It can be integrated with over 60 ESPs/CRM tools. This provides users with versatility and flexibility of functionality, for instance, pushing emails to automation systems with only a click of a button.

3. Mailtrap

MailTrap is an online tool for safe email testing in development and staging environments. The tool is used as a: 

• Fake SMTP server to catch test emails

• View them in virtual inboxes

• Debug before they are sent to real users

MailTrap allows you to test and iterate over new emails efficiently to avoid sending them mistakenly to clients and other employees from dev environments. It can be integrated via API or as an SMTP server and offers numerous features, including Bcc testing. Most email testing tools do not support Bcc, as it is not a regular SMTP header like To or Cc. 

MailTrap displays all Cc’ed addresses and can verify whether they stay invisible for the main recipients. It also provides a customizable email address for each inbox, allowing you to run tests in a production environment in addition to a development environment.

4. Email On Acid

Email on Acid is an email platform specializing in quality assurance and pre-deployment functionality. It enhances organizations’ ability to deliver error-free emails that ultimately maintain brand reputation to boost marketing ROI. Email on Acid strives to provide consistent visual email rendering across different devices and platforms, ensuring generated emails are displayed as intended. It streamlines the email testing and pre-deployment process with: 

• Campaign prechecks

• URL validation

• Image optimization

Email on Acid allows you to run checklists that matter, such as UTM validation and ADA compliance. Email on Acid improves email deliverability rates with spam checks in addition to providing access to blacklisted domains. This allows developers and email designers to verify their email list against over 20 popular spam filters while testing IP addresses against popular block list services.

5. GlockApps

GlockApps is an inbox delivery and spam filter testing tool that allows users to fix email deliverability problems before hitting send. GlockApps provides a one-stop-shop for all email delivery tools, including a “Reputation Check,” which will enable you to audit your IP address and domain you are sending from against industry blacklists. You can also access DMARC email analytics to: 

• Monitor

• Capture

• Separate

• Reject

Glockapps provides detailed spam and blacklist reports to allow the user to troubleshoot and fix problems that improve email deliverability. This feature is handy should you wish to test marketing campaigns and the deliverability of email marketing providers. The report shows all IP addresses that were used to send emails and details whether they are on any blacklists, allowing you to get an overall view of the email campaign’s performance.

6. MailSlurp

MailSlurp is an “email as a service” tool with: 

• Email sandbox APIs

• Deliverability dashboards

• Auto-forwarding

• Webhooks

• Inbox routing used by: 

• Trivago

• Ring

• Panasonic

Using REST API, the tool allows you to programmatically test transactional emails and fundamental user engagement by sending actual emails to real email addresses for your application. Mainly used by developers and QA testers, MailSlurp allows you to create actual inboxes on demand, send and receive emails and attachments in code, and tests using a variety of frameworks and languages, such as Selenium and Jest. 

MailSlurp uses a custom SMTP MailServer and AWS SES to send and receive your emails at scale. You can send contact group email design templates and track the times an email has been opened using actual email addresses. You can also test user authentication, forgotten passwords, and email verification.

7. Wormly

Wormly is a website uptime monitoring solution that tracks site uptime, CPU usage, and SMTP server testing for new mail servers. Adding a few details to an on-page form allows you to access SMTP testing and remote ping testing for free through their site. Wormly provides detailed website and app uptime reporting and runs on all major operating systems, including Windows and Linux. 

In addition to email testing, Wormly offers a website monitoring service that continually monitors your website infrastructure and will alert you if a failure is detected. This allows you to act quickly and minimize downtime. The tool also offers sensors to monitor TCP/IP services to their full extent, allowing you to see your infrastructure availability and uptime.

8. MailChimp Transactional Email

Mailchimp is an all-in-one marketing platform with a robust content creation suite, marketing analytics, and add-on options for advanced email testing features. Mailchimp is AI-powered and provides user-friendly tools on an intuitive user interface, offering accessibility to users who lack deep technical knowledge. Mailchimp delivers comprehensive reporting on: 

• Deliverability

• Open rates

• Click-throughs

• Conversions

Mailchimp provides marketing automation features to manage transactional deliveries and automate tasks and communications. The tool is scalable, allowing you to send many emails at once. Mailchimp also offers website hosting and design, making it easy for the user to create landing pages from various basic templates (or code your own from scratch).

9. MailCatcher

MailCatcher is an email testing tool designed to intercept all mail from any web or mobile app and store it for display. MailCatcher runs a fake SMTP server and shows: 

• HTML and CSS emails

• Plain Text emails

• Source versions of messages as applicable

It also rewrites HTML, enabling the display of embedded images, and can open links in a new window. This allows you to effectively test all aspects of your email and check the formatting before it goes to your client. MailCatcher mail appears instantly if WebSockets is supported on your browser; otherwise, it updates every thirty seconds. It also offers command-line options to override the default SMTP/HTTP IP and port settings, allowing you to manipulate your testing best for your practice.

10. Litmus ESP

Litmus ESP is an email marketing tool that helps you build, test, and analyze all email service providers (ESPs). Litmus allows you to chart the specific reasons why an email may fail to deliver and see the time taken to load an image and access real-world processing into inboxes. Litmus’s user interface provides fast-loading screenshots allowing you to streamline your processes in: 

• All current email clients

• Organization of emails within one folder system

• Preview testing of email content

• Builder for checking and testing various code against different email clients

The user interface also allows for team commenting and editor functionality. Litmus connects with a wide range of ESPs and other services, including: 

• Acoustic Campaign

• Adobe Campaign Standard

• Adobe Marketo

• Hubspot

• Oracle Eloqua

• Oracle Responsys

• Pardot

• Salesforce Marketing Cloud

• SAP Marketing Cloud

11. MailHog

MailHog is an email testing tool with a fake SMTP server designed specifically for app developers. The tool allows you to configure your application to use MailHog for: 

• SMTP delivery

• View messages in a web UI

• Retrieve them with the JSON API

• Optionally release messages to real SMTP servers for delivery

MailHog is a lightweight tool that you do not have to install therefore it can be run on multiple operating systems, including: 

• Windows

• Linux

• MacOS

This allows developers to easily test a web app’s email-sending and receiving capabilities. MailHog also provides real-time updates using an EventSource web interface. Captured emails can be stored in in-memory message storage and persisted in a MongoDB and file-based stored system.

12. Mailosaur

Next on our list of email testing software options is Mailosaur. This tool is excellent if you’re looking for something simple and effective for testing emails. 

You’ll get features like: 

• Automated testing email framework and language Integration of testing results into an existing dashboard 

• User interaction simulations 

• Automated testing of account verification and password resets 

• Unlimited email addresses for testing 

This email test tool will provide everything you need to test your emails and produce the perfect email for your clients.

13. ReachMail

Next on our list of email testing tools is ReachMail. ReachMail offers solutions for small businesses and large companies. With this tool, you can A/B test your emails. A/B testing involves testing two slightly different versions of your email to determine which one performs better. It’s a great solution to help you craft the perfect email. 

ReachMail enables you to test up to five emails at a time and look at the data to help you make your decisions. This process makes it easy to sample your audience and see what emails they like best so you can create more compelling emails for your subscribers.

14. SocketLabs

Socketlabs is an excellent option for testing your SMTP relay service, giving users: 

• Easy configuration options

• Reporting tools

• A dedicated IP address and much more

With the platform, you can send marketing and transactional emails by integrating the tool with your apps or through Socketlabs’ Control Panel. Moreover, the tool significantly improves your email delivery through its advanced reporting capabilities. More specifically, you can access detailed reports showcasing: 

• Failed messages

• Deliverability issues

• Engagement and more

SocketLabs features: 

• Deliverability insights 

• StreamScore™ delivery reporting 

• Automatic bounce processing 

• Dedicated IP address 

• Reporting API

15. MxToolBox

MxToolBox’s delivery service is equipped with various tools to help you identify potential issues and improve your SMTP Server security. The platform will also help you keep track of your: 

• MX record

• DNS, blacklists

• SMTP analytics

All you have to do is add your domain name and IP address/hostname, and you will be ready to roll. Apart from that, MxToolBox’s super tool will allow you to run various tests, including: 

• HTTP/HTTPS verification

• SPF and TXT record check

• ICMP pinging

• Trace routing

• DNS server troubleshooting

MxToolBox features: 

• Mail server testing 

• Real-time deliverability insights 

• Blacklist monitoring 

• Inbound and outbound 

• Mailflow monitoring 

• Email Health check option

16. Spam Check by Postmark

While Postmark is an SMTP email delivery service, it has a few handy email testing tools to help you detect potential issues using SpamAssassin. The platform will give you free access to its Spam Check tool. You can quickly run your tests by adding your email code to the tool and using the JSON API to connect spam score processing in your applications. If you want to take advantage of Postmark’s platform as an SMTP relay service, you will have to get one of the available paid plans. 

Spam Check features: 

• Lightweight JSON API 

• SpamAssassin score 

• Spam score processing 

• Easy-to-use interface

17. ZeroBounce 

ZeroBounce is among the popular email verification tools you can try to ensure your emails reach your recipients’ inboxs. The service is perfect for cleaning your email lists through the bulk email verifier. On top of that, you can easily connect ZeroBounce’s email validation API with your newsletter signup forms to perform real-time checks that will save you valuable time. Apart from email validation, the email testing tool offers additional features to run email deliverability tests and detect mail server errors. 

ZeroBounce features: 

• Email verification tester 

• Quality scoring for contacts 

• Email deliverability test option 

• Blacklist monitoring 

• Email validation API

18. MailFloss

Mailfloss will enable you to “floss” your email lists from harmful or fake email addresses. To do it, the service lets you connect with your favorite email platform to remove invalid contacts and maintain a good sender reputation and sender score. The tool is also perfect for newbies as it requires zero coding knowledge. 

Nevertheless, you can benefit from Mailfloss’ real-time API if you're more on the tech side. You can upload your spreadsheets or add email addresses manually for more traditional users. 

Mailfloss features: 

• Automatic daily cleaning 

• Real-time API 

• Invalid address auto-removal 

• Detailed analytics and stats 

• Integration with popular ESPs

19. EmailListVerify

EmailListVerify will assist you in validating your email list addresses. All you need is to upload your contacts (accepted formats include CSV, XLS, TXTX, etc.) and in a few minutes, you can download a clean list that won’t damage your email deliverability. Apart from its list verification abilities, the platform is capable of: 

• Validating your SMTP server and domain

• Running spam checks

• Performing MX record tests to increase your email ROI and help you succeed.

EmailListVerify features: 

• Email health checker 

• Blacklist tests 

• MX lookup 

• Email address extractor 

• SMTP server validation

20. Reply

Reply offers visibility and complete control over your email account health, from tech setup to inbox placement, within a full-fledged sales engagement platform. You can ensure the proper technical setup of your email account by automatically checking the validity and authentication of your essential DNS records, including:

• SPF

• DKIM

• DMARC

• Domain age, etc. 

You can also use the tool to build or repair your sender’s reputation. Simply put, the platform will send many emails to trusted peer accounts (other users) and automatically interact with the emails on your behalf, closely imitating human behavior. Your sender's reputation will also improve as the sending limit gradually increases daily. But the best part is that you get real-time insights into your account’s performance and track the progress with detailed reports. 

Reply features: 

• DNS issue detection 

• AI-generated templates 

• Multiple service profiles 

• Peer-to-peer sending 

• Ramp-Up mode

21. Folderly

Folderly offers a complete suite of tools to test, monitor, and automatically improve your email deliverability. It is a complex platform that helps you identify and fix any issues that might arise with your domain or email account. Folderly offers an automated email warm-up service. In addition, there are some helpful add-ons, including the SPF Generator and Email Placement Test. 

If you want more help, you can also request professional help from their in-house experts, including deliverability audits and even order template writing services. 

Folderly features: 

• Custom API integration 

• Email placement test 

• Domain status monitoring 

• Email content analysis 

• Detailed account dashboard

22. VWO 

VWO is one of the most popular email testing tools in the market regarding split and multivariate testing. This means that you can A/B test any element of your email campaign and measure the performance of your new variants. Marketers can quickly launch new tests through the point-and-click editor to increase their email open rates and find the winning campaign versions. This testing software will let you run multivariate tests compared to other tools. You can try numerous combos to see what works best for your audience! 

VWO features: 

• Email split test options 

• Point-and-click visual editor 

• Ready-to-use widgets 

• AI copy generator 

• Segmentation-based tests

23. Optimizely

Optimizely is another testing platform that you can use to run concurrent experiments that will improve your marketing plan. The platform sports advanced tools to experiment with different elements to optimize your messages and increase your overall engagement. Besides your email A/B Tests, Optimizely will give you the means to test your website through their visual editor. This way, you can try different UI variants to personalize your website messages and convert more visitors. 

Optimizely features: 

• Digital experience tool 

• Web experimentation 

• No code visual editor 

• Multivariate testing Rollout tool

24. Refine by Moosend

Refine is Moosend’s free subject line tester tool you can use on the spot. To access it, you just need to go to the tool, insert your subject line, choose your industry and subscribers, and then hit the “Predict Now” button. The AI-powered software will rate your subject line against the industry average and suggest how to improve its performance. If your subject line needs optimization, Refine will suggest essential changes like adding: 

• Emojis

• Personalization

• Other elements that will fine-tune your messages

Refine features: 

• Ever-advancing algorithm 

• Very easy to use 

• Tailored to each industry 

• Optimization options

25. Send Check It

Send Check It is a simple yet effective solution to detect problems in your email subject lines. The software is accessible by anyone as long as you have an email address. When you add your subject line, the tool will automatically analyze it and provide you with information such as: 

• Your performance score

• Scannability

• Reading level

• Length

You’ll get useful recommendations on how to improve your subject line, including personalization and punctuation suggestions. 

Send Check It features: 

• Subject line scoring 

• Spam word detection 

• Sentiment analysis for marketing emails 

• Big subject line database

26. SendForensics

SendForensics is an advanced email deliverability suite that uses multiple AI insights to gauge an email’s ability to reach your recipient’s inbox. This tool evaluates your email’s quality against global filtering-systems/ISPs, including human recipients. Adding SendForensics to your email toolbox allows you to monitor your: 

• Sending infrastructure

• Email content (including links)

• IPs

• Domains

• Other things that can impact deliverability

As a bonus, this testing tool has email preview functionality. 

SendForensics features: 

• Email client preview testing 

• Live inbox placement testing 

• Predictive deliverability score 

• DMARC compliance verification 

• Blacklist and whitelist monitoring 

• Email content analysis and optimization 

• Infrastructure analysis and optimization 

• ISP (Internet Service Provider) reputation analysis 

• AI-driven insights into email content

• Sending infrastructure and reputation

27.  Clearout

‍Clearout is a great email verification tool with features similar to ZeroBounce. Like ZeroBounce, this tool stands out because it validates a subscriber’s email from the point of capture. So whether you intend to capture emails, you can verify emails before they make it to your list via: 

• Your website

• Exit pop-ups

• WooCommerce checkouts

• Surveys/polls

• Chatbots

• Newsletters 

This prunes your list of invalid subscribers from the get-go, limits the chances of hard bounces, and ‌improves deliverability. Also, Clearout cleans your list of email duplicates, has spam detection algorithms, and verifies if your recipient’s mailbox can accept new emails. 

Clearout features: 

• Gibberish check for identifying random email addresses Integrates with 100+ apps 

• Duplicate email removal 

• Greylisting verification 

• Blacklist monitoring 

• Spam trap detection 

• Simple API

28.  Lemwarm by Lemlist 

‍Lemwarm is one of the best email warm-up tools that helps you wave goodbye to spam folders. The tool operates by progressively sending and engaging with small amounts of personalized emails, depending on your email domain’s age. Best part? Rather than sending and responding to emails using fake accounts, Lemwarm exchanges emails with 20,000+ people from over 100 countries. The result? Your sender reputation is high, and your emails reach your recipients’ primary inboxes. 

Lemwarm features: 

• Real people, no fake accounts 

• Warms up any email domain 

• 25+ years domain age range 

• Email deliverability booster

29. AutoWarmer by QuickMail

AutoWarmer is another powerful email-warming tool like the others on this list. One of its perks is the availability of a free-forever plan. While the free plan is great if you’re on a budget, it limits your access to only warming inboxes on Gmail/Outlook/SMTP. You’d need to upgrade to a paid plan to use functionalities like the warm-up deliverability report. 

AutoWarmer features: 

• Tracking of email opens and clicks 

• Automated stop on reply 

• Automated follow-ups 

• Bounce detection 

• Live notifications A/B testing

30. CoSchedule email subject line analyzer

This is one of the best tools for assessing the quality of your email subject lines. This tool in your email arsenal allows you to gain insights into what can increase your open rate. With CoSchedule email subject line tester, you’ll see: 

• The previews of your subject line on desktop and mobile

• Words that can increase

• Decrease opens and a subject line score. 

The best part? This email subject line analyzer is a free tool.

Related Reading

• How Long Should a Cold Email Be
• B2B Cold Email Response Rates
• How to Improve Email Deliverability
• Unlimited Email Hosting
• Best Cold Email Software
• Best Email Deliverability Tools
• Mailscale Alternatives
• Sales Email Automation Tools
• Email Scraping Tools
• Mailforge Alternatives
• Best Sales Prospecting Tools
• Email Warm Up Tools
• Email Personalization Tools

What Should You Look for In Email Testing Tools?

Compatibility and Rendering: Ensure Your Email Looks Good Everywhere 

Choose an email testing tool that shows how your email will look across various clients and devices. This is crucial because emails from popular email service providers such as Gmail, Outlook, or mobile devices can appear differently on different email clients. 

Spam Testing: Reach Your Audience 

Ensure your emails reach their intended recipients and are not flagged as spam. Your chosen tool should be able to ensure high deliverability rates and assess your: 

• Subject line

• Email content

• Sender reputation 

Link and Image Validation: Avoid Broken Emails 

Opt for a tool that identifies broken links and image issues to ensure seamless inbox management. If the tool also offers inbox insights and email preview, even better. 

Load Time Analysis: Speed Up Your Emails 

Ensure your email testing tool analyzes elements that impact load time, such as image size and external scripts. This helps reduce abandonment rates—which is critical for those managing meeting invites and other time-sensitive emails. 

User Interface and Ease of Use: Make It Simple 

A testing tool that is easy to navigate and use, even for the less technically inclined, can improve email productivity. 

Integration Capabilities: Consider Compatibility 

You should also consider how well the tool integrates with your current email marketing platform and other tools. Smooth integration can further streamline your workflow. 

Customer Support: You’re Not Alone 

Look for tools offering: 

• Robust customer support

• Including tutorials

• Customer service

• Chat support

• Troubleshooting help

Good support is invaluable, especially when dealing with complex email management issues. 

Feedback and Collaboration Features: Work Together 

Pick a tool that allows users to collaborate on activities such as sharing tests and gathering feedback. This is especially important if you work in a team. 

Related Reading

• Amazon SES Alternatives
• Cold Email Marketing Services
• Maildoso Alternatives
• Sendgrid Alternatives
• Lemlist vs Instantly
• Smartlead vs Instantly
• Mailgun Alternatives
• Cold Email Services
• Mailreef

Start Buying Domains Now and Setup Your Email Infrastructure Today

At Inframail, we are revolutionizing cold email infrastructure with unlimited inboxes at a flat rate. We provide: 

• Microsoft-backed deliverability

• Dedicated IP addresses

• Automated technical setup 

 It helps: 

• Agencies

• Recruiters

• Sales development representatives 

Our service boasts automated: 

• SPF

• DKIM

• DMARC setup

• Dedicated email servers for each user

• 16-hour priority support daily

Unlike traditional providers that charge per inbox and leave you wrestling with technical configurations, Inframail streamlines the entire process. We handle the complex infrastructure setup while you focus on reaching more prospects. 

InfraMail provides the robust email infrastructure you need without the usual technical headaches and per-inbox costs, whether you're an: 

• Agency looking to scale outreach

• A recruiter connecting with candidates

• An SDR driving sales

Start buying domains now and setup your email infrastructure today!