Email testing and validation

You can test key user journeys that involve email interactions using mabl Mailbox. For example, your test can test registering a user account, receiving verification email, clicking a link to verify the email address, and asserting that the email has been verified.


Enterprise feature

This feature is available to customers on the Enterprise plan, as well as all mabl trials.

What is mabl Mailbox?

Mailbox is an email service that mabl offers to help you test emails sent by your application under test. When training a test, you can generate a unique email address that the app can send emails to. You can then interact with and assert against all received emails using the mabl Trainer.

With mabl Mailbox, you can do the following:

  • Create end-to-end tests that include email validation without the need for scripting or complex setups
  • Follow links from emails in the same end-to-end test
  • Capture screenshots of the email message and detect visual changes over time
  • Validate attachments and their metadata
  • Keep test emails safe in a highly secure mailbox.

Unlike traditional email testing approaches, email testing with mabl enables you to validate that there are no issues with your web application's email service provider. Traditional email testing approaches typically intercept the emails sent by the app before they reach the email server and thus cannot alert you about issues with your email server or service provider. In mabl, if there were such an issue, those emails will not reach your mabl Mailbox, and the test run will fail.

Use cases

Mabl Mailbox is intended to be used for workflows that take an email address as an input, such as:

  • User account registration
  • Web form submission notifications (e.g. Contact us)
  • Sending reports, invoices, reminders, etc. to user emails
  • Verifying attachments


Mailbox limitations

  • Your form validations and mail provider should support email addresses up to 25 characters long
  • Email address must be an input to the test and generated by mabl (not user supplied)
  • Email total size must be under 10 MiB (e.g. with attachments)
  • Mailbox email can only be received (asserted) in the same test that generated the address
  • Email must arrive within 5 minutes of the email assertion step, or the assertion will be failed

Learn more

To get started with this feature, see the next guide on using mabl Mailbox.