Malpit is a powerful, user-friendly email testing tool designed for developers, offering a safe sandbox environment to intercept, inspect, and test emails without sending them to real recipients. It acts as a local SMTP server, capturing emails sent during development and displaying them in a web interface with various viewing options, including HTML, plain text, and raw source. Malpit’s features include real-time updates via WebSockets, HTML and spam checks, link validation, message tagging, and support for MIME attachments with image thumbnails. It also offers advanced capabilities like chaos testing for simulating network failures, a REST API for automated testing, and SMTP relaying for forwarding inspected emails to real recipients. Malpit is easy to install and use, with support for multiple platforms, including Docker, and integrates seamlessly with applications by redirecting emails to its SMTP port.