A developer tool for testing email sending by capturing SMTP traffic and providing a web UI and API to inspect messages.
MailHog is an open-source email testing tool that acts as a fake SMTP server for development environments. It captures outgoing emails sent by applications, allowing developers to inspect them through a web interface or API without actually delivering them to real recipients. This helps developers test email functionality, debug email content, and ensure proper email delivery workflows during development.
Developers and QA engineers working on applications that send emails, particularly those in web development, microservices, or any software with email notification features.
MailHog provides a lightweight, self-contained solution for email testing that's easier to install and run than many alternatives. Its real-time web UI, comprehensive API, and support for releasing emails to real servers make it versatile for both development and testing scenarios.
Web and API based SMTP testing
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Built with Go, MailHog runs without installation on multiple platforms, as emphasized in the README with simple download-and-run instructions for various OS.
The web UI uses EventSource for live updates, allowing developers to instantly view captured emails in plain text, HTML, or raw source format, as shown in the screenshot and features list.
Offers JSON API v1 and v2 to programmatically list, retrieve, and delete messages, enabling automated testing in CI/CD pipelines, detailed in the API documentation.
Includes 'Jim' chaos monkey to simulate SMTP server issues like timeouts or errors, helping test application resilience, as described in the features and JIM documentation.
Supports in-memory, MongoDB, and file-based storage for message persistence, catering to different development needs, as noted in the configuration and features sections.
Designed solely for development and testing; it lacks features for actual email delivery, tracking, or compliance required in production environments, as implied by its focus on fake SMTP capture.
While it supports basic SMTP AUTH and PIPELINING, it doesn't handle advanced email testing scenarios like spam filtering, detailed bounce management, or encryption beyond basic setups.
Using MongoDB or file storage requires external configuration and dependencies, adding setup overhead compared to the default in-memory storage, which may not suit all teams.
MailHog is an open-source alternative to the following products: