MailHandler is a simple Ruby library designed for email delivery testing, built on top of the Ruby Mail gem. It aims to provide a stopwatch-like experience for testing email delivery, allowing developers to easily send and search for emails, gather statistics about sending and receiving times, and receive notifications about long searches or delays. The library also supports searching by local folders and files, making it suitable for testing email delivery in various environments, including Postmark and SMTP servers. MailHandler can be used as a standalone tool or integrated into test suites using Ruby frameworks like RSpec. Its features include sending emails, receiving notifications, and analytics tracking, making it a versatile tool for email delivery testing and development.