Bounce Emulator

You can test your SMTP client’s behavior when the server responds with an error using the Email Testing Bounce Emulator. 

It creates a special recipient address with an encoded bounce response. 

How to use Bounce Emulator

Constructing the address

The recipient’s username should start with bounce+ and contain the response in URL-encoded form: bounce+550+no+such+user+here@inbox.mailtrap.io.

To create it, use https://www.urlencoder.org or any other URL encoding solution.

Tip: You cannot use capital letters because email addresses are converted to lowercase by any responsible SMTP client. But you can use URL encoding to express capital letters: bounce+550+%4Eo+such+user+here@inbox.mailtrap.io.

Using Bounce Emulator with an email client

Just use the inbox.mailtrap.io host with any email client or application and send an email to bounce+451+server+unavailable@inbox.mailtrap.io. 

Using Bounce Emulator with Email Testing

If your application is connected to Email Testing SMTP, send an email from the application to bounce+454+authentication+required@anydomain.com, and your application will receive a bounce response from the Mailtrap SMTP server.

Note: This feature does not work with API, as bounce codes are specific to SMTP.