Mailpit is an email and SMTP testing tool that captures and inspects emails during development.
The tool solves the problem of testing email functionality without sending real messages to external addresses. It works by running as an SMTP server that intercepts outgoing mail, storing it in memory for inspection through a web interface. Developers configure their applications to send mail to Mailpit instead of a production mail server, then review captured emails, check formatting, verify links, and test email-related workflows without external dependencies or side effects.
Mailpit suits developers building applications that send email notifications, password resets, or transactional messages. It is particularly useful for integration testing where you need to verify email content and behavior programmatically. The tool provides a REST API for automated testing, allowing test suites to query captured emails and assert on their contents. The project explicitly positions itself as a successor to MailHog, which is no longer maintained, offering a maintained alternative with active security updates.
The project maintains active continuous integration across testing, building, and Docker image generation. Code quality is monitored through automated analysis. The tool is built in Go with zero external dependencies, resulting in a single binary that runs on multiple platforms with minimal resource consumption.
