Email Sending simulator from Amazon SES

Amazon Simple Email Service (Amazon SES) provides a mailbox simulator that you can use to test how your application handles various email sending scenarios without affecting your sending quota or your bounce and complaint metrics. The Amazon SES mailbox simulator is a set of test email addresses. Each email address represents a specific scenario.

Although it is for Amazon SES, It is good for testing even your Email sending includes other providers.

When you send emails to the mailbox simulator, you will be limited by your maximum send rate. You will also be billed for your emails. However, emails to the mailbox simulator will not affect your email deliverability metrics for bounces and complaints or count against your sending quota.
You can send emails to the mailbox simulator when you want to:

• Test your application without having to create test "To" addresses.
• Test how your email sending program handles bounces, complaints, and out-of-the-office (OOTO) responses.
• See what happens when you email an address that is on the Amazon SES suppression list.
• Generate a bounce without putting a valid email address on the suppression list.
• Find your system's maximum throughput without using up your daily sending quota.
• Send test emails without affecting your email deliverability metrics for bounces and complaints.