10 Best Email Testing Tools For Optimized Delivery [2021] Featured Image

10 Best Email Testing Tools For Optimized Delivery [2022]

Email testing is often neglected, however, is important considering how many emails are sent a day by a single person working at a company. Sometimes, the problem is finding the right tool for your company and your situation.  

In this article, I have selected a shortlist of just some of the best email testing tools in the market. With a range of tools suitable for developers, QA testers, and email marketers alike, there is something for every level of expertise.  

The Best Email Testing Tools List

Here’s the list of the best email testing software and apps that I’ll cover in this article.

  1. GlockApps
  2. Mail-Tester
  3. MailCatcher
  4. MailHog
  5. MailSlurp
  6. Mailchimp Transactional Email
  7. Wormly
  8. Sendinblue
  9. Mailtrap
  10. Litmus ESP

Comparison Criteria

What do I look for when I select the best email testing solutions? Here’s a summary of my evaluation criteria: 

  1. User Interface (UI): I look for user-friendly and clean dashboards for pleasant user experience, ensuring everything is clear, concise and organized.
  2. Usability: I look for effective but easy to use platforms with extensive documentation for reference and training.
  3. Integrations: I look for easy and efficient email integration opportunities through various social media platforms, email providers such as Gmail and Outlook, and analytics that are easily executed.
  4. Value for $: I look for what features and access levels you get for your money—is it worth what you’re paying?

Email Testing: Key Features

  1. Email Integration: Email testing tools should work with all the most popular email providers, including Gmail, Outlook, AOL, iCloud, and so on.
  2. Spam Tests: Email testing tools should be able to detect whether or not your email campaigns can make it through common spam filters.
  3. Sender Score: The software should give you an idea of your sender score—AKA how likely you are to be able to make it in front of your target audience.
  4. Defect tracking: If a problem arises, the tool should appropriately flag and log it so that your team can address it in a timely fashion.
  5. Deliverability optimization: The platform should provide insights that improve your likelihood of emails reaching their target destination. 

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Overviews Of The 10 Best Email Testing Tools

Here’s a brief description of each email testing platform to showcase each tool’s best use case, some noteworthy features, and screenshots to give a snapshot of the interface. 

1. GlockApps – Best for spam testing email campaigns 

GlockApps Email Testing Tool Screenshot
Use the Email Message Spam feature to check if your emails are going to spam.

GlockApps is an inbox delivery and spam filter testing tool that allows users to fix any email deliverability problems prior to hitting send. GlockApps provides a one-stop-shop for all email delivery tools including a “Reputation Check,” which allows you to audit your IP address and domain you are sending from against industry blacklists. You also have access to DMARC Email Analytics to monitor, capture, separate and or/reject any email pretending to be you.

Glockapps provides detailed spam and blacklist reports in order to allow the user to troubleshoot and fix problems that improve email deliverability. This feature is particularly useful should you wish to test marketing campaigns and 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.

GlockApps costs from $59/month for the basic plan, and also provides a free version specifically for personal use.

2. MailTester – Best for ease-of-use email testing

MailTester Email Testing Tool Screenshot
MailTester Email Testing Tool Screenshot
Check your sender reputation spam score using MailTester’s spam checker.

MailTester is a cloud-based email verification solution that helps businesses verify the domains and syntax of emails. The tool is an effective first line of defense for email testing and provides an easy to use user interface, allowing accessibility to users lacking technical knowledge. 

MailTester offers an extensive toolbox which includes Spam Trap Removal (searches for spam trap emails in your email lists) and Syntax Verifier (catches emails containing invalid syntaxes and deletes them). MailTester allows manual as well as automatic email verification using API and allows you to download segmented results.

MailTester costs from $19/month for 1 user. They also offer a free trial.

3. MailCatcher – Best free email testing tool

MailCatcher Email Testing Tool Screenshot
MailCatcher can help you test regularly scheduled email campaigns, like renewal reminders, before they go out.

MailCatcher is an email testing tool that is 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 and Source versions of messages as applicable. It also rewrites HTML enabling 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, which allows you to manipulate your testing the best way for

your practice.

MailCatcher is a free email testing tool and instructions on how to download it can be found on their site.

4. MailHog – Best for app developers

MailHog Email Testing Tool Screenshot
MailHog lets testers view emails using a web user interface for free, no download (or payment) required.

MailHog is an email testing tool with a fake SMTP server that is 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, or retrieve them with the JSON API, and 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 and MacOS. This allows easy access for developers to test 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 database and file-based stored system.

MailHog is an open source and free tool that can be used by anyone. 

5. MailSlurp – Best for end-to-end email testing

MailSlurp Email Testing Tool Screenshot
MailSlurp helps you test a variety of email campaign components, including link validity, site loading, and CTA (ie. account sign up) health.

MailSlurp is an “email as a service” tool with email sandbox APIs, deliverability dashboards, auto-forwarding, webhooks, and inbox routing that is used by the likes of Trivago, Ring, and 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 to your

application. Used primarily by developers and QA testers, MailSlurp allows you to create real

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 groups email design templates and track the number of times an email has been opened using actual email addresses, test user authentication, forgotten passwords and email verification.

MailSlurp costs from $21.66/month (billed annually) for the Starter package.

MailSlurp also offers a 7-day free trial.

6. Mailchimp Transactional Email – Best for marketing automations

MailChimp Transactional Email Testing Tool Screenshot
Mailchimp Transactional Email is an add-on for those already using the platform; start sending via their Transactional API or SMTP integration.

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 offers comprehensive reporting for deliverability, open rates, click-throughs, and conversions. 

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

To get access to the Transactional Email add-on, you’ll need a Standard Mailchimp plan or above: $14.99/month. Then, add $20/block (AKA 25,000 emails)—or, access lower per-block rates for bulk purchases.

7. Wormly – Best for email + web monitoring

Wormly Email Testing Tool Screenshot
Wormly can handle both email testing as well as website monitoring services for QA teams who need both.

Wormly is a website uptime monitoring solution that tracks things like site uptime, CPU usage, and SMTP server testing for new mail servers. You can access SMTP testing and Remote Ping testing for free through their site by adding a few details into an on-page form. 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 which continually monitors your website infrastructure and will alert you if a failure is detected, allowing you to act quickly and minimize downtime. The tool also offers sensors to monitor TCP/IP services to their full extent which allows you to get a picture of your infrastructure availability and uptime.

Wormly costs from $39/month for 10 test targets at 1-min frequency (1 user). They offer some free services on their website. Paid plans come with a free trial. 

8. Sendinblue – Best for small to medium enterprises

Sendinblue Email Testing Tool Screenshot
Sendinblue’s mail testing suite lets you create IF/THEN statements for email contact vetting, account confirmation workflows, and resend campaigns.

Sendinblue is an email and marketing automation tool designed specifically for small to medium enterprises. Sendinblue boasts a full, easy-to-use marketing hub, including automation features, email validation, reporting and email design templates. Sendinblue’s email automation tool lets you send rules and execute commands depending on end user action.

Sendinblue provides targeted communication using behavioural, email and contact data, helping you to build basic and advanced workflows and separate your contacts and email list based on website activity. Their jack-of-all-trades approach to email creation, marketing, automation, and testing is something that many SMEs prefer over juggling an endless email tech stack. 

The cost of Sendinblue starts at $25/month for up to 10,000 emails. Sendinblue also offers a free version with some account limitations

9. MailTrap – Best for email testing in staging environments

MailTrap Email Testing Tool Screenshot
Organize your projects on the easy to use Mailtrap dashboard.

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, and debug before they are sent to real users. MailTrap allows you to test and iterate over new emails efficiently in order to avoid emails mistakenly being sent to clients and other employees from dev environments. MailTrap can be integrated via API or as an SMTP server.

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

The cost of MailTrap starts at $9.99/ month for 1 user and up to 5 inboxes. MailTrap also offers a free version specifically for a single inbox and up to 500 email tests per month.

10. Litmus ESP – Best for integrations

Litmus ESP Email Testing Tool Screenshot
Generate multiple email previews with Litmus’s extensive preview and testing suite

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, as well as allow you to see the time taken to load an image and have accessibility to real world processing into inboxes. 

Litmus’s user interface provides fast loading screenshots of all current email clients, organization of emails within one folder system, preview testing of email content and a Builder for checking and testing various code against different email clients, allowing you to streamline your processes. 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, and SAP Marketing Cloud. 

The cost for Litmus ESP starts at $79/month for the basic package. The tool also offers a 7-day free trial.  

Other Options

Here’s a few more that didn’t make the top list.

  1. Stripo – Free drag-and-drop email creation tool with 5 daily test emails as a part of the entry level plan. 
  2. Email on Acid – Easy email testing tool with UTM validation, accessibility checks, GIF checking, and more.
  3. SparkPost – Email sender reputation tool using data-driven analytics to parse bounce, delivery, and engagement events.
  4. Mailosaur – API for automating your email tests—works with frameworks like Cypress, Selenium, and Webdriver.io.
  5. ZeroBounce – Email validation service that uses AI-powered deliverability scoring to increase your deliverability and open rates.


So: should QAs care about email testing? Short answer is YES! 

Email testing is important as a part of a broader brand communication and marketing strategy. These tools are designed to improve deliverability and minimize risk when sending out hoards of emails to clients, each tool also harbouring their own specific strength so that you are able to make an informed decision based on your needs. 

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